Species Name
Preferred Formula
Image
Δf H°(0 K)
Δf H°(298.15 K)
Uncertainty
Units
Relative Molecular Mass
ATcT ID
Dihydrogen H2 (g) 0 0 exact 2.01588 ± 0.00014 1333-74-0*0 Helium He (g) 0 0 exact 4.0026020 ± 0.0000020 7440-59-7*0 Carbon atom C (graphite) 0 0 exact 12.01070 ± 0.00080 7440-44-0*500 Dinitrogen N2 (g) 0 0 exact 28.01348 ± 0.00014 7727-37-9*0 Dioxygen O2 (g) 0 0 exact 31.99880 ± 0.00060 7782-44-7*0 Difluorine F2 (g) 0 0 exact 37.9968064 ± 0.0000010 7782-41-4*0 Neon Ne (g) 0 0 exact 20.17970 ± 0.00060 7440-01-9*0 Silicon Si (cr,l) 0 0 exact 28.08550 ± 0.00030 7440-21-3*500 Dichlorine Cl2 (g) 0 0 exact 70.9054 ± 0.0018 7782-50-5*0 Argon Ar (g) 0 0 exact 39.94800 ± 0.00100 7440-37-1*0 Dibromine Br2 (cr,l) 0 0 exact 159.8080 ± 0.0020 7726-95-6*500 Krypton Kr (g) 0 0 exact 83.8000 ± 0.1000 7439-90-9*0 Diiodine I2 (cr,l) 0 0 exact 253.808940 ± 0.000060 7553-56-2*500 Xenon Xe (g) 0 0 exact 131.2900 ± 0.0200 7440-63-3*0 Deuterium molecule D2 (g) 0 0 exact 4.02820355600 ± 0.00000000080 7782-39-0*0 Hydrogen atom H (g) 216.034 217.998 ± 0.000 kJ/mol 1.007940 ± 0.000070 12385-13-6*0 Carbon atom C (g) 711.397 716.882 ± 0.047 kJ/mol 12.01070 ± 0.00080 7440-44-0*0 Oxygen atom O (g) 246.844 249.229 ± 0.0021 kJ/mol 15.99940 ± 0.00030 17778-80-2*0 Nitrogen atom N (g) 470.579 472.442 ± 0.024 kJ/mol 14.006740 ± 0.000070 17778-88-0*0 Carbon dioxide CO2 (g) -393.108 -393.474 ± 0.015 kJ/mol 44.00950 ± 0.00100 124-38-9*0 Methane CH4 (g) -66.560 -74.529 ± 0.050 kJ/mol 16.04246 ± 0.00085 74-82-8*0 Chlorine atom Cl (g) 119.621 121.302 ± 0.0011 kJ/mol 35.45270 ± 0.00090 22537-15-1*0 Ethane CH3CH3 (g) -68.39 -84.02 ± 0.13 kJ/mol 30.0690 ± 0.0017 74-84-0*0 Fluorine atom F (g) 77.262 79.368 ± 0.048 kJ/mol 18.99840320 ± 0.00000050 14762-94-8*0 Water H2O (cr,l) -286.302 -285.830 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*500 Water H2O (g) -238.932 -241.835 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*0 Hydron H+ (g) 1528.084 1530.047 ± 0.000 kJ/mol 1.007391 ± 0.000070 12408-02-5*0 Ethylene CH2CH2 (g) 60.84 52.33 ± 0.12 kJ/mol 28.0532 ± 0.0016 74-85-1*0 Bromine atom Br (g) 117.917 111.855 ± 0.056 kJ/mol 79.90400 ± 0.00100 10097-32-2*0 Methyl CH3 (g) 149.864 146.449 ± 0.056 kJ/mol 15.03452 ± 0.00083 2229-07-4*0 Methanol CH3OH (g) -190.06 -200.95 ± 0.16 kJ/mol 32.04186 ± 0.00090 67-56-1*0 Propane CH3CH2CH3 (g) -82.80 -105.08 ± 0.18 kJ/mol 44.0956 ± 0.0025 74-98-6*0 Hydroxyl OH (g) 37.249 37.488 ± 0.026 kJ/mol 17.00734 ± 0.00031 3352-57-6*0 Hydrogen chloride HCl (g) -91.989 -92.173 ± 0.0062 kJ/mol 36.46064 ± 0.00090 7647-01-0*0 Carbon monoxide CO (g) -113.803 -110.523 ± 0.026 kJ/mol 28.01010 ± 0.00085 630-08-0*0 Formaldehyde CH2O (g) -105.378 -109.217 ± 0.097 kJ/mol 30.02598 ± 0.00087 50-00-0*0 Ethanol CH3CH2OH (g) -217.32 -235.04 ± 0.22 kJ/mol 46.0684 ± 0.0017 64-17-5*0 Hydrogen fluoride HF (g) -272.670 -272.717 ± 0.048 kJ/mol 20.006343 ± 0.000070 7664-39-3*0 Acetylene HCCH (g) 228.82 228.26 ± 0.13 kJ/mol 26.0373 ± 0.0016 74-86-2*0 Hydrogen bromide HBr (g) -27.66 -35.51 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*0 Ammonia NH3 (g) -38.565 -45.558 ± 0.029 kJ/mol 17.03056 ± 0.00022 7664-41-7*0 Iodine I (g) 107.157 106.757 ± 0.0021 kJ/mol 126.904470 ± 0.000030 14362-44-8*0 Ethyl CH3CH2 (g) 131.02 119.95 ± 0.26 kJ/mol 29.0611 ± 0.0016 2025-56-1*0 Hydrogen cyanide HCN (g) 129.660 129.276 ± 0.090 kJ/mol 27.02538 ± 0.00081 74-90-8*0 Nitric oxide NO (g) 90.619 91.123 ± 0.065 kJ/mol 30.00614 ± 0.00031 10102-43-9*0 Chloromethane CH3Cl (g) -74.32 -82.25 ± 0.25 kJ/mol 50.4872 ± 0.0012 74-87-3*0 Propene CH3CHCH2 (g) 34.89 19.89 ± 0.20 kJ/mol 42.0797 ± 0.0024 115-07-1*0 Nitrogen dioxide ONO (g) 36.859 34.052 ± 0.065 kJ/mol 46.00554 ± 0.00060 10102-44-0*0 Hydrogen iodide HI (g) 28.646 26.470 ± 0.036 kJ/mol 127.912410 ± 0.000076 10034-85-2*0 Benzene C6H6 (g) 100.61 83.10 ± 0.23 kJ/mol 78.1118 ± 0.0048 71-43-2*0 Hydroxyde [OH]- (g) -139.093 -139.059 ± 0.026 kJ/mol 17.00789 ± 0.00031 14280-30-9*0 Dioxidanyl HO2 (g) 15.12 12.22 ± 0.15 kJ/mol 33.00674 ± 0.00060 3170-83-0*0 Acetaldehyde CH3CHO (g) -155.08 -165.56 ± 0.25 kJ/mol 44.0526 ± 0.0017 75-07-0*0 Fluoromethane CH3F (g) -227.45 -235.48 ± 0.23 kJ/mol 34.03292 ± 0.00083 593-53-3*0 Hydrogen peroxide H2O2 (g) -129.479 -135.465 ± 0.063 kJ/mol 34.01468 ± 0.00062 7722-84-1*0 Propyne CH3CCH (g) 192.74 185.68 ± 0.23 kJ/mol 40.0639 ± 0.0024 74-99-7*0 Bromomethane CH3Br (g) -20.27 -35.67 ± 0.26 kJ/mol 94.9385 ± 0.0013 74-83-9*0 n-Butane CH3CH2CH2CH3 (g) -98.47 -125.78 ± 0.25 kJ/mol 58.1222 ± 0.0033 106-97-8*0 Methylene CH2 (g, singlet) 428.72 429.13 ± 0.11 kJ/mol 14.02658 ± 0.00081 2465-56-7*2 Formic acid HC(O)OH (g, syn) -371.11 -378.43 ± 0.22 kJ/mol 46.0254 ± 0.0010 64-18-6*1 Methylene CH2 (g, triplet) 391.060 391.617 ± 0.097 kJ/mol 14.02658 ± 0.00081 2465-56-7*1 Hypochlorous acid HOCl (g) -73.869 -76.808 ± 0.027 kJ/mol 52.46004 ± 0.00095 7790-92-3*0 Tetrafluoromethane CF4 (g) -927.49 -933.46 ± 0.25 kJ/mol 88.00431 ± 0.00080 75-73-0*0 Vinyl CH2CH (g) 301.16 296.96 ± 0.32 kJ/mol 27.0452 ± 0.0016 2669-89-8*0 Dibromine Br2 (g) 45.68 30.89 ± 0.12 kJ/mol 159.8080 ± 0.0020 7726-95-6*0 Acetone CH3C(O)CH3 (g) -200.11 -216.80 ± 0.36 kJ/mol 58.0791 ± 0.0025 67-64-1*0 Tetrachloromethane CCl4 (g) -93.42 -95.59 ± 0.43 kJ/mol 153.8215 ± 0.0037 56-23-5*0 Methylamine CH3NH2 (g) -6.62 -21.33 ± 0.26 kJ/mol 31.05714 ± 0.00088 74-89-5*0 Fluoride F- (g) -250.903 -249.118 ± 0.048 kJ/mol 18.99895178 ± 0.00000050 16984-48-8*0 Ketene CH2CO (g) -45.35 -48.47 ± 0.11 kJ/mol 42.0367 ± 0.0016 463-51-4*0 Chloroethane CH3CH2Cl (g) -96.90 -111.48 ± 0.26 kJ/mol 64.5138 ± 0.0019 75-00-3*0 Phenyl C6H5 (g) 350.41 337.05 ± 0.52 kJ/mol 77.1039 ± 0.0048 2396-01-2*0 Allene CH2CCH2 (g) 197.30 189.82 ± 0.25 kJ/mol 40.0639 ± 0.0024 463-49-0*0 Methylidyne CH (g) 592.820 596.154 ± 0.098 kJ/mol 13.01864 ± 0.00080 3315-37-5*0 Methoxide [CH3O]- (g) -122.63 -130.36 ± 0.28 kJ/mol 31.03447 ± 0.00088 3315-60-4*0 Nitrilomethyl CN (g) 436.75 440.04 ± 0.14 kJ/mol 26.01744 ± 0.00080 2074-87-5*0 Acetonitrile CH3CN (g) 81.10 74.04 ± 0.25 kJ/mol 41.0520 ± 0.0016 75-05-8*0 1,3-Butadiene CH2CHCHCH2 (g) 125.29 110.81 ± 0.34 kJ/mol 54.0904 ± 0.0032 106-99-0*0 Oxonium [H3O]+ (g) 605.85 599.10 ± 0.17 kJ/mol 19.02267 ± 0.00037 13968-08-6*0 Diiodine I2 (g) 65.497 62.417 ± 0.0041 kJ/mol 253.808940 ± 0.000060 7553-56-2*0 Methoxy CH3O (g) 28.76 21.39 ± 0.28 kJ/mol 31.03392 ± 0.00088 2143-68-2*0 Acetic acid CH3C(O)OH (g, syn) -418.86 -432.98 ± 0.42 kJ/mol 60.0520 ± 0.0017 64-19-7*1 Ozone OOO (g) 144.397 141.735 ± 0.039 kJ/mol 47.99820 ± 0.00090 10028-15-6*0 Toluene C6H5CH3 (g) 73.29 50.00 ± 0.34 kJ/mol 92.1384 ± 0.0056 108-88-3*0 Fluoroform CHF3 (g) -689.04 -695.99 ± 0.41 kJ/mol 70.01385 ± 0.00080 75-46-7*0 Trifluoromethyl CF3 (g) -464.95 -467.74 ± 0.48 kJ/mol 69.00591 ± 0.00080 2264-21-3*0 Ethylium [CH3CH2]+ (g) 914.92 902.85 ± 0.30 kJ/mol 29.0606 ± 0.0016 14936-94-8*0 Phenol C6H5OH (g) -74.80 -93.39 ± 0.63 kJ/mol 94.1112 ± 0.0048 108-95-2*0 Hydroxymethyl CH2OH (g) -10.49 -16.80 ± 0.28 kJ/mol 31.03392 ± 0.00088 2597-43-5*0 Chloride Cl- (g) -228.953 -227.346 ± 0.0021 kJ/mol 35.45325 ± 0.00090 16887-00-6*0 Bromide Br- (g) -206.620 -212.682 ± 0.056 kJ/mol 79.90455 ± 0.00100 24959-67-9*0 Hypobromous acid HOBr (g) -51.53 -62.01 ± 0.47 kJ/mol 96.9113 ± 0.0010 13517-11-8*0 Formyl HCO (g) 41.392 41.768 ± 0.097 kJ/mol 29.01804 ± 0.00086 2597-44-6*0 iso-Butane CH(CH3)3 (g) -106.02 -134.63 ± 0.30 kJ/mol 58.1222 ± 0.0033 75-28-5*0 Chlorooxidanyl ClO (g) 101.125 101.716 ± 0.035 kJ/mol 51.45210 ± 0.00095 14989-30-1*0 Oxomethylium [HCO]+ (g) 827.768 827.183 ± 0.097 kJ/mol 29.01749 ± 0.00086 17030-74-9*0 Methyl hydroperoxide CH3OOH (g) -115.17 -127.99 ± 0.50 kJ/mol 48.0413 ± 0.0010 3031-73-0*0 Imidogen NH (g) 358.74 358.78 ± 0.16 kJ/mol 15.014680 ± 0.000099 13774-92-0*0 Propargyl CH2CCH (g) 353.97 351.37 ± 0.35 kJ/mol 39.0559 ± 0.0024 2932-78-7*0 Dioxymethyl CH2OO (g) 111.84 104.84 ± 0.62 kJ/mol 46.0254 ± 0.0010 56077-92-0*0 Difluorophosgene CF2O (g) -603.34 -606.44 ± 0.41 kJ/mol 66.00691 ± 0.00085 353-50-4*0 Formamide CH(O)NH2 (g) -178.54 -188.90 ± 0.36 kJ/mol 45.04066 ± 0.00088 75-12-7*0 Cyanoacetylene HCCCN (g) 372.00 373.74 ± 0.64 kJ/mol 51.0468 ± 0.0024 1070-71-9*0 Nitric acid HON(O)O (g) -124.49 -134.20 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*0 Amidogen NH2 (g) 188.91 186.02 ± 0.11 kJ/mol 16.02262 ± 0.00016 13770-40-6*0 Allyl CH2CHCH2 (g) 179.97 168.25 ± 0.44 kJ/mol 41.0718 ± 0.0024 1981-80-2*0 Ethenol CH2CHOH (g, syn) -113.12 -124.30 ± 0.52 kJ/mol 44.0526 ± 0.0017 557-75-5*1 Vinyl chloride CH2CHCl (g) 29.27 21.69 ± 0.30 kJ/mol 62.4979 ± 0.0018 75-01-4*0 Methylium [CH3]+ (g) 1099.336 1095.393 ± 0.051 kJ/mol 15.03397 ± 0.00083 14531-53-4*0 Iodide I- (g) -187.995 -188.396 ± 0.0021 kJ/mol 126.905019 ± 0.000030 20461-54-5*0 Cyanogen chloride ClCN (g) 134.97 135.66 ± 0.46 kJ/mol 61.4701 ± 0.0012 506-77-4*0 Methylperoxy CH3OO (g) 22.05 12.60 ± 0.37 kJ/mol 47.0333 ± 0.0010 2143-58-0*0 Hydroxyformyl HOCO (g, trans) -181.13 -184.09 ± 0.44 kJ/mol 45.0174 ± 0.0010 2564-86-5*1 Isocyanic acid HNCO (g) -115.98 -118.97 ± 0.30 kJ/mol 43.02478 ± 0.00086 75-13-8*0 Hypofluorous acid HOF (g) -84.39 -87.29 ± 0.19 kJ/mol 36.00574 ± 0.00031 14034-79-8*0 Hydrogen chloride HCl (aq, 600 H2O) -166.452 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*834 Ethoxide [CH3CH2O]- (g) -163.87 -178.81 ± 0.48 kJ/mol 45.0610 ± 0.0017 16331-64-9*0 Dichloromethane CH2Cl2 (g) -86.54 -93.40 ± 0.52 kJ/mol 84.9320 ± 0.0020 75-09-2*0 Chlorobenzene C6H5Cl (g) 67.14 52.18 ± 0.61 kJ/mol 112.5566 ± 0.0049 108-90-7*0 Cyanogen bromide BrCN (g) 187.0 180.5 ± 1.1 kJ/mol 105.9214 ± 0.0013 506-68-3*0 Iodomethane CH3I (g) 24.51 14.97 ± 0.18 kJ/mol 141.93899 ± 0.00083 74-88-4*0 Trihydrogen cation [H3]+ (g) 1110.304 1106.696 ± 0.013 kJ/mol 3.02327 ± 0.00021 28132-48-1*0 Oxygen atom anion O- (g) 105.868 108.097 ± 0.0021 kJ/mol 15.99995 ± 0.00030 14337-01-0*0 n-Propyl CH3CH2CH2 (g) 118.21 100.81 ± 0.52 kJ/mol 43.0877 ± 0.0024 2143-61-5*0 Acetyl CH3CO (g) -3.60 -10.26 ± 0.33 kJ/mol 43.0446 ± 0.0016 3170-69-2*0 iso-Propyl CH3CHCH3 (g) 105.19 88.31 ± 0.50 kJ/mol 43.0877 ± 0.0024 2025-55-0*0 2-Hydroxyethyl CH2CH2OH (g, gauche-syn) -13.35 -26.62 ± 0.56 kJ/mol 45.0605 ± 0.0017 4422-54-2*1 Tetrabromomethane CBr4 (g) 133.5 103.8 ± 1.3 kJ/mol 331.6267 ± 0.0041 558-13-4*0 Difluoromethane CH2F2 (g) -443.14 -450.75 ± 0.33 kJ/mol 52.02339 ± 0.00081 75-10-5*0 Oxygen difluoride FOF (g) 26.82 24.57 ± 0.24 kJ/mol 53.99621 ± 0.00030 7783-41-7*0 Hypochlorite [ClO]- (g) -118.60 -118.33 ± 0.13 kJ/mol 51.45265 ± 0.00095 14380-61-1*0 Nitrosyl hydride HNO (g) 109.93 106.96 ± 0.11 kJ/mol 31.01408 ± 0.00032 14332-28-6*0 Isocyanomethane CH3NC (g) 183.52 176.97 ± 0.59 kJ/mol 41.0520 ± 0.0016 593-75-9*0 Cyclopropane CH2(CH2CH2) (g) 70.97 53.84 ± 0.40 kJ/mol 42.0797 ± 0.0024 75-19-4*0 Propynylidene HCCCH (g, triplet) 543.39 546.39 ± 0.63 kJ/mol 38.0480 ± 0.0024 67152-18-5*1 Cyclopentadiene CH2(CHCHCHCH) (g) 151.19 134.07 ± 0.64 kJ/mol 66.1011 ± 0.0040 542-92-7*0 Chloroform CHCl3 (g) -97.17 -102.07 ± 0.50 kJ/mol 119.3767 ± 0.0028 67-66-3*0 Fluoromethylidyne CF (g) 243.14 246.74 ± 0.12 kJ/mol 31.00910 ± 0.00080 3889-75-6*0 Acrylonitrile CH2CHCN (g, singlet) 193.75 186.99 ± 0.66 kJ/mol 53.0627 ± 0.0024 107-13-1*1 Methanimine CH2NH (g) 96.47 88.56 ± 0.40 kJ/mol 29.04126 ± 0.00083 2053-29-4*0 Nitrous acid HONO (g, trans) -73.005 -79.148 ± 0.079 kJ/mol 47.01348 ± 0.00061 7782-77-6*1 1,2-Propadiene-1,3-diylidene CCC (g) 814.68 823.63 ± 0.55 kJ/mol 36.0321 ± 0.0024 12075-35-3*0 Cyanic fluoride FCN (g) 8.77 9.10 ± 0.69 kJ/mol 45.01584 ± 0.00080 1495-50-7*0 1-Hydroxyethyl CH3CHOH (g, gauche-anti) -42.76 -56.19 ± 0.58 kJ/mol 45.0605 ± 0.0017 2348-46-1*1 Formate [HC(O)O]- (g) -463.25 -466.89 ± 0.56 kJ/mol 45.0180 ± 0.0010 71-47-6*0 Methyl formate HC(O)OCH3 (g, syn) -346.88 -359.93 ± 0.84 kJ/mol 60.0520 ± 0.0017 107-31-3*1 Oxygen atom cation O+ (g) 1560.786 1562.644 ± 0.0021 kJ/mol 15.99885 ± 0.00030 14581-93-2*0 Tetrafluoroethylene CF2CF2 (g) -670.99 -674.40 ± 0.53 kJ/mol 100.0150 ± 0.0016 116-14-3*0 Chlorotrifluoromethane CF3Cl (g) -704.53 -709.64 ± 0.57 kJ/mol 104.4586 ± 0.0012 75-72-9*0 Ethyl bromide CH3CH2Br (g) -41.16 -63.11 ± 0.25 kJ/mol 108.9651 ± 0.0019 74-96-4*0 Vinyl bromide CH2CHBr (g) 88.64 73.83 ± 0.58 kJ/mol 106.9492 ± 0.0019 593-60-2*0 Chlorine fluoride ClF (g) -55.614 -55.709 ± 0.055 kJ/mol 54.45110 ± 0.00090 7790-89-8*0 Diazynium [NNH]+ (g) 1042.43 1038.82 ± 0.68 kJ/mol 29.02087 ± 0.00016 12357-66-3*0 Nitrite [ONO]- (g) -182.63 -185.44 ± 0.46 kJ/mol 46.00609 ± 0.00060 14797-65-0*0 Hydroxylamine NH2OH (g, trans) -33.12 -43.50 ± 0.45 kJ/mol 33.02996 ± 0.00037 7803-49-8*1 n-Butyl CH3CH2CH2CH2 (g) 102.71 80.20 ± 0.71 kJ/mol 57.1143 ± 0.0033 2492-36-6*0 Hydride H- (g) 143.264 145.228 ± 0.000 kJ/mol 1.008489 ± 0.000070 12184-88-2*0 Methoxymethane CH3OCH3 (g) -166.47 -183.98 ± 0.40 kJ/mol 46.0684 ± 0.0017 115-10-6*0 Methyl acetate CH3C(O)OCH3 (g, syn) -394.29 -413.16 ± 0.61 kJ/mol 74.0785 ± 0.0025 79-20-9*1 Phosgene CCl2O (g) -217.45 -219.14 ± 0.27 kJ/mol 98.9155 ± 0.0020 75-44-5*0 Vinyl fluoride CH2CHF (g) -134.60 -142.40 ± 0.45 kJ/mol 46.0436 ± 0.0016 75-02-5*0 Phenylium [C6H5]+ (g) 1148.42 1135.64 ± 0.85 kJ/mol 77.1034 ± 0.0048 17333-73-2*0 Fluorooxidanyl FO (g) 110.27 110.90 ± 0.15 kJ/mol 34.99780 ± 0.00030 12061-70-0*0 Hypoiodous acid HOI (g) -54.2 -58.9 ± 3.1 kJ/mol 143.91181 ± 0.00031 14332-21-9*0 Methanium [CH5]+ (g) 921.91 911.67 ± 0.45 kJ/mol 17.04985 ± 0.00087 15135-49-6*0 Oxirane O(CH2CH2) (g) -40.07 -52.61 ± 0.37 kJ/mol 44.0526 ± 0.0017 75-21-8*0 Ethynyl CCH (g) 563.87 567.98 ± 0.14 kJ/mol 25.0293 ± 0.0016 2122-48-7*0 Cyclopropene CH2(CHCH) (g) 292.27 283.54 ± 0.48 kJ/mol 40.0639 ± 0.0024 2781-85-3*0 cis-2-Butene CH3CHCHCH3 (g, cis) 14.20 -7.08 ± 0.41 kJ/mol 56.1063 ± 0.0032 590-18-1*0 Ethynide [CCH]- (g) 277.41 280.82 ± 0.18 kJ/mol 25.0299 ± 0.0016 29075-95-4*0 Formic acid HC(O)OH (g, anti) -354.76 -361.86 ± 0.38 kJ/mol 46.0254 ± 0.0010 64-18-6*2 Methanetetraylbisamidogen NCN (g) 450.42 450.83 ± 0.64 kJ/mol 40.02418 ± 0.00081 2669-76-3*0 Fluoroethane CH3CH2F (g) -257.24 -272.11 ± 0.36 kJ/mol 48.0595 ± 0.0016 353-36-6*0 Bromotrifluoromethane CF3Br (g) -638.88 -651.00 ± 0.45 kJ/mol 148.9099 ± 0.0013 75-63-8*0 Phenide [C6H5]- (g) 244.34 230.91 ± 0.39 kJ/mol 77.1044 ± 0.0048 30922-78-2*0 Fluorobenzene C6H5F (g) -99.09 -114.76 ± 0.89 kJ/mol 96.1023 ± 0.0048 462-06-6*0 Nitromethane CH3N(O)O (g) -60.82 -74.72 ± 0.46 kJ/mol 61.0401 ± 0.0010 75-52-5*0 Acrylonitrile CH2CHCN (g) 193.75 186.99 ± 0.66 kJ/mol 53.0627 ± 0.0024 107-13-1*0 Chlorine dioxide OClO (g) 101.33 98.86 ± 0.27 kJ/mol 67.4515 ± 0.0011 10049-04-4*0 Dioxygen cation [O2]+ (g) 1164.585 1165.221 ± 0.0092 kJ/mol 31.99825 ± 0.00060 12185-07-8*0 Ethynylene C2 (g) 820.33 828.79 ± 0.26 kJ/mol 24.0214 ± 0.0016 12070-15-4*0 Methylidyne CH (g, quartet) 664.55 667.88 ± 0.59 kJ/mol 13.01864 ± 0.00080 3315-37-5*2 Ethanide [CH3CH2]- (g) 155.25 144.17 ± 0.89 kJ/mol 29.0616 ± 0.0016 25013-41-6*0 Aminomethyl CH2NH2 (g) 159.20 149.36 ± 0.38 kJ/mol 30.04920 ± 0.00085 10507-29-6*0 Cyanide [CN]- (g) 63.956 67.242 ± 0.094 kJ/mol 26.01799 ± 0.00080 57-12-5*0 Cyanomethyl CH2CN (g) 263.39 260.51 ± 0.69 kJ/mol 40.0440 ± 0.0016 2932-82-3*0 Peroxyformic acid HC(O)OOH (g, cis) -279.38 -288.73 ± 0.88 kJ/mol 62.0248 ± 0.0012 107-32-4*1 Propadienylidene CH2CC (g) 554.37 555.52 ± 0.41 kJ/mol 38.0480 ± 0.0024 60731-10-4*0 Isobutene CH2C(CH3)2 (g) 4.05 -17.02 ± 0.40 kJ/mol 56.1063 ± 0.0032 115-11-7*0 Ethoxy CH3CH2O (g, X 2A") 1.27 -12.64 ± 0.47 kJ/mol 45.0605 ± 0.0017 2154-50-9*51 Cyanooxidanyl NCO (g) 126.92 127.39 ± 0.34 kJ/mol 42.01684 ± 0.00086 22400-26-6*0 Phenolate [C6H5O]- (g) -146.63 -162.10 ± 0.84 kJ/mol 93.1038 ± 0.0048 3229-70-7*0 Dimethylamine (CH3)2NH (g) 3.83 -17.81 ± 0.46 kJ/mol 45.0837 ± 0.0017 124-40-3*0 Cyclopentadienyl CH(CHCHCHCH) (g) 274.51 261.39 ± 0.92 kJ/mol 65.0932 ± 0.0040 2143-53-5*0 Bromooxidanyl BrO (g) 131.15 123.61 ± 0.28 kJ/mol 95.9034 ± 0.0010 15656-19-6*0 Hypobromite [BrO]- (g) -96.14 -103.62 ± 0.53 kJ/mol 95.9039 ± 0.0010 14380-62-2*0 Hydrogen fluoride HF (aq) -334.50 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*800 Ammonium [NH4]+ (g) 643.02 631.71 ± 0.21 kJ/mol 18.03795 ± 0.00029 14798-03-9*0 (E)-Diazene HNNH (g, trans) 207.09 199.95 ± 0.41 kJ/mol 30.02936 ± 0.00020 15626-43-4*0 Fluorodioxidanyl FOO (g) 26.81 25.10 ± 0.26 kJ/mol 50.99720 ± 0.00060 15499-23-7*0 Peroxynitrous acid HOONO (g, cis, cis) -5.81 -14.25 ± 0.36 kJ/mol 63.01288 ± 0.00091 14691-52-2*3 Ethylidene CH3CH (g, singlet) 373.50 366.27 ± 0.65 kJ/mol 28.0532 ± 0.0016 4218-50-2*2 Cyanogen NCCN (g) 308.17 310.11 ± 0.41 kJ/mol 52.0349 ± 0.0016 460-19-5*0 1-Butene CH2CHCH2CH3 (g) 21.01 0.06 ± 0.36 kJ/mol 56.1063 ± 0.0032 106-98-9*0 n-Pentane CH3CH2CH2CH2CH3 (g) -114.41 -146.28 ± 0.31 kJ/mol 72.1488 ± 0.0041 109-66-0*0 Cyclopentane CH2(CH2CH2CH2CH2) (g) -43.87 -76.44 ± 0.39 kJ/mol 70.1329 ± 0.0041 287-92-3*0 Dichloromethylene CCl2 (g, singlet) 229.51 230.69 ± 0.64 kJ/mol 82.9161 ± 0.0020 1605-72-7*2 Trifluoromethylium [CF3]+ (g) 409.53 406.32 ± 0.47 kJ/mol 69.00536 ± 0.00080 18851-76-8*0 Difluorodioxidane FOOF (g) 35.28 31.55 ± 0.41 kJ/mol 69.99561 ± 0.00060 7783-44-0*0 Dioxidanide [HO2]- (g) -88.87 -91.53 ± 0.34 kJ/mol 33.00729 ± 0.00060 14691-59-9*0 Trioxidane HOOOH (g, trans) -82.01 -90.86 ± 0.63 kJ/mol 50.01408 ± 0.00091 14699-99-1*1 Azido radical NNN (g) 452.27 449.68 ± 0.60 kJ/mol 42.02022 ± 0.00021 12596-60-0*0 Nitrous oxide NNO (g) 85.997 82.568 ± 0.097 kJ/mol 44.01288 ± 0.00033 10024-97-2*0 Hydroxyoxomethylium [HOCO]+ (g) 600.62 597.54 ± 0.44 kJ/mol 45.0169 ± 0.0010 638-71-1*0 Hydroxyamidogen HNOH (g, trans) 101.36 94.53 ± 0.81 kJ/mol 32.02202 ± 0.00034 13940-32-4*1 Hydrazoic acid HNNN (g) 297.92 291.62 ± 0.49 kJ/mol 43.02816 ± 0.00022 7782-79-8*0 Water H2O (l) -285.830 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*590 Ethylidene CH3CH (g, triplet) 361.20 354.20 ± 0.51 kJ/mol 28.0532 ± 0.0016 4218-50-2*1 Vinylium [CH2CH]+ (g) 1119.01 1115.56 ± 0.57 kJ/mol 27.0447 ± 0.0016 14604-48-9*0 Vinylidene CCH2 (g) 411.18 412.09 ± 0.31 kJ/mol 26.0373 ± 0.0016 2143-69-3*0 Hydroxymethylium [CH2OH]+ (g) 717.65 709.71 ± 0.19 kJ/mol 31.03337 ± 0.00088 18682-95-6*0 Fluoroacetylene HCCF (g) 104.95 105.67 ± 0.40 kJ/mol 44.0277 ± 0.0016 2713-09-9*0 Peroxyformyl HC(O)OO (g, syn) -100.58 -105.89 ± 0.92 kJ/mol 61.0168 ± 0.0012 56240-83-6*1 n-Hexane CH3CH2CH2CH2CH2CH3 (g) -130.04 -166.91 ± 0.34 kJ/mol 86.1754 ± 0.0049 110-54-3*0 Ketenyl HCCO (g) 177.06 178.15 ± 0.55 kJ/mol 41.0287 ± 0.0016 51095-15-9*0 Formic acid HC(O)OH (g) -371.11 -378.40 ± 0.22 kJ/mol 46.0254 ± 0.0010 64-18-6*0 Methyl formate HC(O)OCH3 (g, anti) -326.7 -339.2 ± 1.1 kJ/mol 60.0520 ± 0.0017 107-31-3*2 Trichloromethyl CCl3 (g) 72.02 71.55 ± 0.84 kJ/mol 118.3688 ± 0.0028 3170-80-7*0 1,1-Dichloroethane CH3CHCl2 (g) -120.29 -133.07 ± 0.44 kJ/mol 98.9586 ± 0.0024 75-34-3*0 Bromoform CHBr3 (g) 75.7 49.5 ± 1.3 kJ/mol 252.7306 ± 0.0031 75-25-2*0 Bromobenzene C6H5Br (g) 126.7 104.6 ± 1.3 kJ/mol 157.0079 ± 0.0049 108-86-1*0 Benzaldehyde C6H5C(O)H (g) -19.34 -37.14 ± 0.92 kJ/mol 106.1219 ± 0.0056 100-52-7*0 Propionaldehyde CH3CH2CHO (g) -171.37 -186.78 ± 0.25 kJ/mol 58.0791 ± 0.0025 123-38-6*0 Isocyanoacetylene HCCNC (g) 484.5 486.7 ± 1.1 kJ/mol 51.0468 ± 0.0024 66723-45-3*0 Chlorous acid HOClO (g) 25.74 20.68 ± 0.63 kJ/mol 68.4594 ± 0.0011 13898-47-0*0 Iodooxidanyl IO (g) 126.97 125.04 ± 0.82 kJ/mol 142.90387 ± 0.00030 14696-98-1*0 Carbon monoxide cation [CO]+ (g) 1238.306 1241.586 ± 0.026 kJ/mol 28.00955 ± 0.00085 12144-04-6*0 Azanide [NH2]- (g) 114.76 111.89 ± 0.29 kJ/mol 16.02317 ± 0.00016 17655-31-1*0 Aminooxy NH2O (g) 70.92 64.32 ± 0.71 kJ/mol 32.02202 ± 0.00034 13408-29-2*0 Nitrate [ON(O)O]- (g) -300.30 -306.84 ± 0.60 kJ/mol 62.00549 ± 0.00090 14797-55-8*0 Hypofluorite [FO]- (g) -108.84 -108.67 ± 0.48 kJ/mol 34.99835 ± 0.00030 12763-66-5*0 2-Butyne CH3CCCH3 (g) 159.35 146.39 ± 0.52 kJ/mol 54.0904 ± 0.0032 503-17-3*0 Cyanogen iodide ICN (g) 222.6 222.0 ± 1.6 kJ/mol 152.92191 ± 0.00080 506-78-5*0 Formyl anion [HCO]- (g) 11.60 11.98 ± 0.44 kJ/mol 29.01859 ± 0.00086 57340-31-5*0 2-Propynylidyne CCCH (g) 717.99 722.35 ± 0.80 kJ/mol 37.0400 ± 0.0024 53590-28-6*0 Ethoxy CH3CH2O (g, A 2A') 5.53 -8.90 ± 0.47 kJ/mol 45.0605 ± 0.0017 2154-50-9*52 Dicarbon monoxide CCO (g, triplet) 377.12 381.16 ± 0.83 kJ/mol 40.0208 ± 0.0016 12071-23-7*1 Chloromethylene CHCl (g, singlet) 320.27 320.55 ± 0.89 kJ/mol 48.4713 ± 0.0012 2108-20-5*2 Dibromomethane CH2Br2 (g) 25.9 4.5 ± 1.1 kJ/mol 173.8346 ± 0.0022 74-95-3*0 1,1-Difluoroethene CH2CF2 (g) -343.57 -350.63 ± 0.77 kJ/mol 64.0341 ± 0.0016 75-38-7*0 3-Buten-2-one CH3C(O)CHCH2 (g, trans) -95.57 -111.81 ± 0.87 kJ/mol 70.0898 ± 0.0032 78-94-4*1 Urea NH2C(O)NH2 (g) -218.23 -234.63 ± 0.42 kJ/mol 60.05534 ± 0.00091 57-13-6*0 Oxomethaniminium [NH2CO]+ (g) 695.47 688.91 ± 0.88 kJ/mol 44.03217 ± 0.00087 59348-22-0*0 Chlorine trifluoride FCl(F)F (g) -158.6 -162.7 ± 1.2 kJ/mol 92.44791 ± 0.00090 7790-91-2*0 Iodine monochloride ICl (g) 19.024 17.391 ± 0.013 kJ/mol 162.35717 ± 0.00090 7790-99-0*0 Iodotrifluoromethane CF3I (g) -583.45 -589.33 ± 0.50 kJ/mol 195.91038 ± 0.00080 2314-97-8*0 Trinitrogen cation [NNN]+ (g) 1519.43 1516.80 ± 0.89 kJ/mol 42.01967 ± 0.00021 12185-03-4*0 Oxonitrate anion [NO]- (g) 88.09 88.13 ± 0.25 kJ/mol 30.00669 ± 0.00031 14967-78-3*0 Nitrosyl ion [NO]+ (g) 984.487 984.482 ± 0.065 kJ/mol 30.00559 ± 0.00031 14452-93-8*0 Nitrogen sesquioxide ONN(O)O (g) 90.72 86.15 ± 0.15 kJ/mol 76.01168 ± 0.00091 10544-73-7*0 Methylene anion [CH2]- (g) 328.17 328.60 ± 0.19 kJ/mol 14.02713 ± 0.00081 50928-07-9*0 Methylidyne anion [CH]- (g) 475.74 479.07 ± 0.22 kJ/mol 13.01919 ± 0.00080 28604-54-8*0 Ethanium [C2H7]+ (g, bridged C2) 874.32 858.06 ± 0.62 kJ/mol 31.0764 ± 0.0017 24669-33-8*1 Acetylium [CH3CO]+ (g) 666.46 659.17 ± 0.45 kJ/mol 43.0441 ± 0.0016 15762-07-9*0 Hydrogen isocyanide HNC (g) 191.94 192.32 ± 0.33 kJ/mol 27.02538 ± 0.00081 6914-07-4*0 Hydroxymethylene HCOH (g, trans) 112.67 108.90 ± 0.27 kJ/mol 30.02598 ± 0.00087 19710-56-6*1 Chloronium [HClH]+ (g) 881.3 878.2 ± 1.1 kJ/mol 37.46803 ± 0.00091 36658-55-6*0 Carbonic acid C(O)(OH)2 (g, cis-cis) -602.78 -612.95 ± 0.75 kJ/mol 62.0248 ± 0.0012 463-79-6*1 Hydrogen bromide HBr (aq) -120.65 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*800 Peroxyformate [HC(O)OO]- (g, syn) -341.14 -346.59 ± 0.95 kJ/mol 61.0174 ± 0.0012 104960-05-6*1 trans-2-Butene CH3CHCHCH3 (g, trans) 9.38 -11.18 ± 0.39 kJ/mol 56.1063 ± 0.0032 624-64-6*0 Isoprene CH2C(CH3)CHCH2 (g) 96.09 75.57 ± 0.67 kJ/mol 68.1170 ± 0.0040 78-79-5*0 1-Hydroxyethylium [CH3CHOH]+ (g, anti) 608.75 594.32 ± 0.39 kJ/mol 45.0600 ± 0.0017 18682-96-7*1 Ethynol HCCOH (g, singlet) 95.29 92.81 ± 0.80 kJ/mol 42.0367 ± 0.0016 32038-79-2*2 Formyloxidanyl HC(O)O (g, 2A1) -125.91 -127.57 ± 0.56 kJ/mol 45.0174 ± 0.0010 16499-21-1*1 Glyoxal OCHCHO (g, trans) -207.75 -213.38 ± 0.61 kJ/mol 58.0361 ± 0.0017 107-22-2*1 Trimethylamine (CH3)3N (g) 1.72 -27.14 ± 0.89 kJ/mol 59.1103 ± 0.0025 75-50-3*0 1,1,1-Trichloroethane CH3CCl3 (g) -134.33 -144.90 ± 0.48 kJ/mol 133.4033 ± 0.0031 71-55-6*0 Tetrachloroethene CCl2CCl2 (g) -22.3 -23.2 ± 1.1 kJ/mol 165.8322 ± 0.0039 127-18-4*0 Chlorodifluoromethane CHClF2 (g) -476.01 -482.20 ± 0.98 kJ/mol 86.4681 ± 0.0012 75-45-6*0 Fluoromethylene CHF (g, singlet) 148.38 148.67 ± 0.43 kJ/mol 32.01704 ± 0.00080 13453-52-6*2 Fluoroformyl FCO (g) -176.62 -176.03 ± 0.37 kJ/mol 47.00850 ± 0.00085 1871-24-5*0 2-Bromoethanol BrCH2CH2OH (g) -196.19 -220.25 ± 0.53 kJ/mol 124.9645 ± 0.0019 540-51-2*0 Carbon suboxide OCCCO (g) -94.9 -92.8 ± 1.2 kJ/mol 68.0309 ± 0.0025 504-64-3*0 Phenoxy C6H5O (g) 70.83 55.54 ± 0.84 kJ/mol 93.1033 ± 0.0048 2122-46-5*0 1-Cyanovinyl CH2CCN (g) 419.0 418.9 ± 1.1 kJ/mol 52.0547 ± 0.0024 15091-87-9*0 Cyanomethylene HCCN (g, triplet) 479.9 483.3 ± 1.1 kJ/mol 39.0361 ± 0.0016 2612-62-6*1 Phenylperoxy C6H5OO (g) 152.9 135.9 ± 1.4 kJ/mol 109.1027 ± 0.0049 91422-02-5*0 Bromonium [HBrH]+ (g) 925.3 914.5 ± 1.5 kJ/mol 81.9193 ± 0.0010 36658-54-5*0 Hydrazine NH2NH2 (g) 111.59 97.44 ± 0.43 kJ/mol 32.04524 ± 0.00031 302-01-2*0 Methanide [CH3]- (g) 141.10 137.66 ± 0.24 kJ/mol 15.03507 ± 0.00083 15194-58-8*0 Methyliumyl [CH2]+ (g) 1393.19 1394.05 ± 0.11 kJ/mol 14.02603 ± 0.00081 15091-72-2*0 Vinyl anion [CH2CH]- (g) 237.00 232.58 ± 0.82 kJ/mol 27.0458 ± 0.0016 25012-81-1*0 Ethylidyne CH3C (g, quartet) 640.7 636.1 ± 1.1 kJ/mol 27.0452 ± 0.0016 67624-57-1*2 Aminomethylium [CH2NH2]+ (g) 763.90 751.93 ± 0.65 kJ/mol 30.04865 ± 0.00085 488821-23-4*0 Isocyanomethanide [CH2NC]- (g) 253.8 250.7 ± 1.0 kJ/mol 40.0446 ± 0.0016 81704-80-5*0 1-Methylethylidene CH3CCH3 (g, singlet) 315.92 302.02 ± 0.99 kJ/mol 42.0797 ± 0.0024 40852-89-9*2 1-Methylethenyl CH3CCH2 (g) 263.00 252.61 ± 0.73 kJ/mol 41.0718 ± 0.0024 15552-77-9*0 Hydrogen chloride HCl (aq) -166.991 ± 0.023 kJ/mol 36.46064 ± 0.00090 7647-01-0*800 iso-Pentane CH3CH2CH(CH3)2 (g) -119.16 -153.21 ± 0.43 kJ/mol 72.1488 ± 0.0041 78-78-4*0 1-Hydroxyethyl CH3CHOH (g, gauche-syn) -41.32 -54.79 ± 0.80 kJ/mol 45.0605 ± 0.0017 2348-46-1*2 Protonated oxirane [(CH2CH2)OH]+ (g) 725.54 709.37 ± 0.62 kJ/mol 45.0600 ± 0.0017 *38607-31-7*0 Methanediol CH2(OH)2 (g, conrot gauche) -379.41 -393.61 ± 0.92 kJ/mol 48.0413 ± 0.0010 463-57-0*1 Trioxidanide [HOOO]- (g, gauche) -120.0 -123.1 ± 1.6 kJ/mol 49.00669 ± 0.00090 89965-38-8*2 Methoxyethane CH3CH2OCH3 (g) -194.38 -217.27 ± 0.57 kJ/mol 60.0950 ± 0.0025 540-67-0*0 Acetic acid CH3C(O)OH (g, anti) -397.87 -411.65 ± 0.83 kJ/mol 60.0520 ± 0.0017 64-19-7*2 Acetyl chloride CH3C(O)Cl (g) -232.59 -241.59 ± 0.33 kJ/mol 78.4973 ± 0.0019 75-36-5*0 Chlorohydroxymethyl CH(Cl)OH (g, syn-gauche) -54.8 -60.8 ± 1.1 kJ/mol 65.4787 ± 0.0012 147139-06-8*1 1,1-Dichloroethene CH2CCl2 (g) 8.94 2.95 ± 0.49 kJ/mol 96.9427 ± 0.0024 75-35-4*0 Hydrogen peroxide cation [H2O2]+ (g, trans) 897.23 890.25 ± 0.51 kJ/mol 34.01413 ± 0.00062 12325-10-9*1 Dichlorodifluoromethane CF2Cl2 (g) -489.46 -493.64 ± 0.67 kJ/mol 120.9129 ± 0.0020 75-71-8*0 Fluorodichloromethane CHFCl2 (g) -278.14 -283.59 ± 0.91 kJ/mol 102.9224 ± 0.0020 75-43-4*0 Difluoromethylene CF2 (g, singlet) -193.90 -193.43 ± 0.38 kJ/mol 50.00751 ± 0.00080 2154-59-8*2 Fluoromethylene CHF (g, triplet) 210.36 210.70 ± 0.66 kJ/mol 32.01704 ± 0.00080 13453-52-6*1 Formyl fluoride CHFO (g) -378.63 -382.22 ± 0.31 kJ/mol 48.01644 ± 0.00086 1493-02-3*0 Benzyl C6H5CH2 (g) 229.96 211.15 ± 0.60 kJ/mol 91.1305 ± 0.0056 2154-56-5*0 Methyl nitrite CH3ONO (g, cis) -55.68 -67.46 ± 0.46 kJ/mol 61.0401 ± 0.0010 624-91-9*2 Carbamoyl NH2CO (g) -7.50 -13.91 ± 0.83 kJ/mol 44.03272 ± 0.00087 2858-51-7*0 Acetamide CH3C(O)NH2 (g) -219.50 -237.01 ± 0.58 kJ/mol 59.0672 ± 0.0017 60-35-5*0 2-Cyanovinyl CHCHCN (g, syn) 447.9 445.5 ± 1.2 kJ/mol 52.0547 ± 0.0024 189141-20-6*2 Dichloride [Cl2]- (g) -229.8 -228.7 ± 1.4 kJ/mol 70.9059 ± 0.0018 12595-89-0*0 Hypoiodite [IO]- (g) -102.47 -104.29 ± 0.88 kJ/mol 142.90442 ± 0.00030 15065-65-3*0 Dinitrogen cation [N2]+ (g) 1503.311 1503.312 ± 0.000 kJ/mol 28.01293 ± 0.00014 13966-04-6*0 Carbon dioxide cation [CO2]+ (g) 936.092 936.927 ± 0.017 kJ/mol 44.00895 ± 0.00100 12181-61-2*0 Chlorine atom cation Cl+ (g) 1370.806 1372.602 ± 0.0011 kJ/mol 35.45215 ± 0.00090 24203-47-2*0 Ammonium [NH4]+ (aq) -133.076 ± 0.056 kJ/mol 18.03795 ± 0.00029 14798-03-9*800 Hydrazino NH2NH (g) 234.71 224.19 ± 0.69 kJ/mol 31.03730 ± 0.00025 13598-46-4*0 Methylamidogen CH3NH (g) 187.50 176.85 ± 0.47 kJ/mol 30.04920 ± 0.00085 15622-51-2*0 Methyleneamidogen CH2N (g) 242.00 238.34 ± 0.58 kJ/mol 28.03332 ± 0.00082 15845-29-1*0 (E)-Iminomethyl HCNH (g, trans) 275.79 272.17 ± 0.61 kJ/mol 28.03332 ± 0.00082 54980-10-8*0 Hydrogen isocyanide cation [HNC]+ (g) 1352.9 1352.9 ± 1.3 kJ/mol 27.02483 ± 0.00081 74158-11-5*0 Chloroacetylene HCCCl (g) 228.12 228.98 ± 0.70 kJ/mol 60.4820 ± 0.0018 593-63-5*0 Hydroperoxonium [H2OOH]+ (g, trans) 738.1 727.8 ± 1.2 kJ/mol 35.02207 ± 0.00064 70850-26-9*1 iso-Propylium [CH3CHCH3]+ (g) 822.86 805.78 ± 0.25 kJ/mol 43.0871 ± 0.0024 19252-53-0*0 n-Propylide [CH3CH2CH2]- (g) 122.8 105.2 ± 1.2 kJ/mol 43.0882 ± 0.0024 59513-13-2*0 1-Propenyl CH3CHCH (g, cis) 278.28 267.43 ± 0.75 kJ/mol 41.0718 ± 0.0024 6067-68-1*2 1,2-Propadienyl anion [CH2CCH]- (g) 265.66 262.60 ± 0.69 kJ/mol 39.0565 ± 0.0024 64066-06-4*0 Propargylenide [HCCCH]- (g, transoid 2B) 434.4 436.9 ± 1.1 kJ/mol 38.0485 ± 0.0024 82906-05-6*1 t-Butyl (CH3)3C (g) 74.98 49.69 ± 0.77 kJ/mol 57.1143 ± 0.0033 1605-73-8*0 neo-Pentane C(CH3)4 (g) -134.63 -167.51 ± 0.40 kJ/mol 72.1488 ± 0.0041 463-82-1*0 Cyclobutane CH2(CH2CH2CH2) (g) 52.31 27.77 ± 0.40 kJ/mol 56.1063 ± 0.0032 287-23-0*0 Cyclobutene CH2(CH2CHCH) (g) 177.44 160.39 ± 0.72 kJ/mol 54.0904 ± 0.0032 822-35-5*0 1-Butyne CH3CH2CCH (g) 179.55 165.97 ± 0.62 kJ/mol 54.0904 ± 0.0032 107-00-6*0 Chloro hypochlorite ClOCl (g) 79.78 77.97 ± 0.36 kJ/mol 86.9048 ± 0.0018 7791-21-1*0 2-Hydroxyethyl CH2CH2OH (g, gauche-anti) -10.80 -23.44 ± 0.82 kJ/mol 45.0605 ± 0.0017 4422-54-2*2 Ketene CH2CO (g, triplet) 182.0 177.0 ± 1.1 kJ/mol 42.0367 ± 0.0016 463-51-4*1 Oxoethylidene HCC(O)H (g, syn-triplet) 261.1 257.6 ± 1.1 kJ/mol 42.0367 ± 0.0016 39920-84-8*12 Methanediol CH2(OH)2 (g, disrot gauche) -369.11 -382.27 ± 0.95 kJ/mol 48.0413 ± 0.0010 463-57-0*2 Chlorine pentafluoride FCl(F)(F)(F)F (g) -226.1 -234.2 ± 1.7 kJ/mol 130.44472 ± 0.00090 13637-63-3*0 Methoxyethene CH2CHOCH3 (g, cis) -89.2 -107.1 ± 1.1 kJ/mol 58.0791 ± 0.0025 107-25-5*2 Methyl acetate CH3C(O)OCH3 (g, anti) -363.4 -382.2 ± 1.2 kJ/mol 74.0785 ± 0.0025 79-20-9*2 Carboxymethyl CH2C(O)OH (g, syn) -227.4 -237.3 ± 1.2 kJ/mol 59.0440 ± 0.0017 2887-46-9*1 (Methylamino)methyl CH3NHCH2 (g) 167.74 151.29 ± 0.96 kJ/mol 44.0758 ± 0.0017 31277-24-4*0 Dimethylamidogen (CH3)2N (g) 173.8 156.5 ± 1.5 kJ/mol 44.0758 ± 0.0017 15337-44-7*0 Cyanoamidogen HNCN (g) 323.9 321.4 ± 1.4 kJ/mol 41.03212 ± 0.00082 12347-01-2*0 Bromotrichloromethane CCl3Br (g) -32.71 -41.86 ± 0.59 kJ/mol 198.2728 ± 0.0030 75-62-7*0 Chloromethylidyne CCl (g) 430.43 434.18 ± 0.67 kJ/mol 47.4634 ± 0.0012 3889-76-7*0 Chloromethanol CH2(Cl)OH (g) -232.3 -242.5 ± 1.2 kJ/mol 66.4866 ± 0.0013 15454-33-8*0 Chlorooxy hypochlorite ClOOCl (g) 134.56 131.32 ± 0.56 kJ/mol 102.9042 ± 0.0019 12292-23-8*0 Chloromethoxy CH2(Cl)O (g) -11.9 -18.8 ± 1.1 kJ/mol 65.4787 ± 0.0012 114282-89-2*0 Tetraiodomethane CI4 (g) 332.2 327.1 ± 4.1 kJ/mol 519.62858 ± 0.00081 507-25-5*0 Fluorotrichloromethane CCl3F (g) -285.27 -288.43 ± 0.78 kJ/mol 137.3672 ± 0.0028 75-69-4*0 2-Chloroethanol ClCH2CH2OH (g) -249.81 -266.52 ± 0.59 kJ/mol 80.5132 ± 0.0019 107-07-3*0 o-Benzyne C6H4 (g, singlet) 468.00 459.09 ± 0.87 kJ/mol 76.0960 ± 0.0048 462-80-6*2 Peroxyhypochlorous acid HOOCl (g) 3.94 -1.33 ± 0.95 kJ/mol 68.4594 ± 0.0011 67952-07-2*0 Tropyl CH(CHCHCHCHCHCH) (g) 295.7 278.3 ± 1.1 kJ/mol 91.1305 ± 0.0056 3551-27-7*0 Iodobenzene C6H5I (g) 177.69 161.70 ± 0.99 kJ/mol 204.0084 ± 0.0048 591-50-4*0 Acetonyl CH3C(O)CH2 (g) -19.06 -31.77 ± 0.98 kJ/mol 57.0712 ± 0.0024 3122-07-4*0 Trifluoroethene CF2CHF (g) -493.1 -498.1 ± 1.6 kJ/mol 82.0245 ± 0.0016 359-11-5*0 Isocyanoethene CH2CHNC (g) 285.02 278.51 ± 0.95 kJ/mol 53.0627 ± 0.0024 14668-82-7*0 1-Isocyanoethylidene CH3CNC (g, singlet) 527.7 523.0 ± 1.1 kJ/mol 53.0627 ± 0.0024 *498544-34-6*2 Cyclobutadiene CH(CHCHCH) (g) 435.78 427.32 ± 0.90 kJ/mol 52.0746 ± 0.0032 1120-53-2*0 Nitrogen atom cation N+ (g) 1872.907 1875.689 ± 0.024 kJ/mol 14.006191 ± 0.000070 14158-23-7*0 Dioxodiazoxane ONONO (g, t, t) 93.0 87.9 ± 1.3 kJ/mol 76.01168 ± 0.00091 122413-35-8*1 Nitric acid HON(O)O (aq) -206.64 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*800 Chlorate [OCl(O)O]- (g) -207.3 -212.8 ± 1.6 kJ/mol 83.4514 ± 0.0013 14866-68-3*0 Chloric acid HOCl(O)O (g) 2.1 -5.0 ± 1.6 kJ/mol 84.4588 ± 0.0013 7790-93-4*0 Isodiazene NNH2 (g) 307.51 300.43 ± 0.63 kJ/mol 30.02936 ± 0.00020 28647-38-3*0 Difluoride [F2]- (g) -291.0 -290.2 ± 1.5 kJ/mol 37.9973550 ± 0.0000010 12184-85-9*0 Oxoammoniumyl [HNO]+ (g) 1092.46 1089.53 ± 0.67 kJ/mol 31.01353 ± 0.00032 63559-87-5*0 Trioxidane HOOOH (g, cis) -72.74 -81.23 ± 0.82 kJ/mol 50.01408 ± 0.00091 14699-99-1*2 Nitryl hydride HN(O)O (g) -36.6 -43.6 ± 1.1 kJ/mol 47.01348 ± 0.00061 90266-90-3*0 Peroxynitrous acid HOONO (g, trans, perp) 7.77 0.69 ± 0.41 kJ/mol 63.01288 ± 0.00091 14691-52-2*1 Carbon anion C- (g) 589.621 594.767 ± 0.047 kJ/mol 12.01125 ± 0.00080 14337-00-9*0 Ethylidyne CH3C (g) 508.51 504.81 ± 0.80 kJ/mol 27.0452 ± 0.0016 67624-57-1*0 Ethynylium [CCH]+ (g) 1687.58 1690.91 ± 0.16 kJ/mol 25.0288 ± 0.0016 16456-59-0*0 Methylamidogen anion [CH3NH]- (g) 145.23 134.40 ± 0.65 kJ/mol 30.04975 ± 0.00085 54448-39-4*0 Iminomethyl cation [HCNH]+ (g) 953.3 949.2 ± 1.4 kJ/mol 28.03277 ± 0.00082 196216-36-1*0 Fluoronium [HFH]+ (g, singlet) 774.11 771.17 ± 0.88 kJ/mol 21.01373 ± 0.00014 12206-67-6*2 Water dimer (H2O)2 (g) -491.084 -499.124 ± 0.052 kJ/mol 36.03056 ± 0.00066 25655-83-8*0 Methylperoxy anion [CH3OO]- (g) -90.38 -100.52 ± 0.49 kJ/mol 47.0339 ± 0.0010 35683-44-4*0 Propylidyne CH3CH2C (g, doublet) 492.4 482.7 ± 1.2 kJ/mol 41.0718 ± 0.0024 85056-54-8*1 Cyclopropylidene C(CH2CH2) (g, singlet) 474.89 466.87 ± 0.85 kJ/mol 40.0639 ± 0.0024 2143-70-6*1 Propargylium [CH2CCH]+ (g) 1193.44 1190.63 ± 0.35 kJ/mol 39.0554 ± 0.0024 21540-27-2*0 Propargylenide [HCCCH]- (g, cisoid 2A) 436.9 439.4 ± 1.1 kJ/mol 38.0485 ± 0.0024 82906-05-6*2 2-Propyn-1-ylium-1-ylidene [CCCH]+ (g) 1598.1 1602.5 ± 1.3 kJ/mol 37.0395 ± 0.0024 75104-46-0*0 Bromanylium Br+ (g) 1257.778 1251.715 ± 0.057 kJ/mol 79.90345 ± 0.00100 22541-56-6*0 1,2-Butadiene CH3CHCCH2 (g) 175.82 162.32 ± 0.46 kJ/mol 54.0904 ± 0.0032 590-19-2*0 Cyclohexane CH2(CH2CH2CH2CH2CH2) (g) -83.44 -123.01 ± 0.33 kJ/mol 84.1595 ± 0.0049 110-82-7*0 Hydrogen fluoride HF (aq, 20 H2O) -321.05 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*818 Ethenol CH2CHOH (g, anti) -108.75 -119.45 ± 0.60 kJ/mol 44.0526 ± 0.0017 557-75-5*2 Vinoxy CH2CHO (g) 22.96 16.12 ± 0.68 kJ/mol 43.0446 ± 0.0016 6912-06-7*0 Oxoethanide [CH3CO]- (g) -44.0 -49.5 ± 1.3 kJ/mol 43.0452 ± 0.0016 78944-68-0*0 Oxirene O(CHCH) (g, singlet) 273.18 271.02 ± 0.92 kJ/mol 42.0367 ± 0.0016 157-18-6*2 Hydroxyformyl HOCO (g, cis) -174.31 -177.34 ± 0.50 kJ/mol 45.0174 ± 0.0010 2564-86-5*2 Hydroxyformyl anion [HOCO]- (g, cis) -319.52 -322.11 ± 0.58 kJ/mol 45.0180 ± 0.0010 78944-70-4*2 Ethoxyethane CH3CH2OCH2CH3 (g) -222.96 -250.38 ± 0.82 kJ/mol 74.1216 ± 0.0033 60-29-7*0 2-Hydrotrioxy OO(H)O (g) 299.6 293.9 ± 1.2 kJ/mol 49.00614 ± 0.00090 *12500-78-6*0 Acetone enol CH3C(OH)CH2 (g, syn) -152.0 -169.4 ± 1.1 kJ/mol 58.0791 ± 0.0025 29456-04-0*1 Acetate [CH3C(O)O]- (g) -496.6 -505.7 ± 1.2 kJ/mol 59.0446 ± 0.0017 71-50-1*0 (Dimethylamino)methyl (CH3)2NCH2 (g) 165.5 142.5 ± 1.3 kJ/mol 58.1024 ± 0.0025 30208-47-0*0 Chloromethide [CH2Cl]- (g) 56.4 53.2 ± 2.0 kJ/mol 49.4798 ± 0.0012 60291-29-4*0 Hexachloroethane CCl3CCl3 (g) -147.0 -149.3 ± 1.3 kJ/mol 236.7376 ± 0.0056 67-72-1*0 cis-1,2-Dichloroethene CHClCHCl (g, cis) 3.47 -2.53 ± 0.54 kJ/mol 96.9427 ± 0.0024 156-59-2*0 Dichloroacetylene ClCCCl (g) 230.12 233.43 ± 0.94 kJ/mol 94.9268 ± 0.0024 7572-29-4*0 Difluoromethylene CF2 (g) -193.90 -193.43 ± 0.38 kJ/mol 50.00751 ± 0.00080 2154-59-8*0 Hexafluoroethane CF3CF3 (g) -1334.13 -1342.43 ± 0.98 kJ/mol 138.0118 ± 0.0016 76-16-4*0 1,1-Difluoroethane CH3CHF2 (g) -489.00 -502.72 ± 0.56 kJ/mol 66.0500 ± 0.0016 75-37-6*0 2-Fluoroethanol FCH2CH2OH (g) -405.85 -423.09 ± 0.99 kJ/mol 64.0589 ± 0.0017 371-62-0*0 1,3-Butadiyne HCCCCH (g) 457.86 459.58 ± 0.76 kJ/mol 50.0587 ± 0.0032 460-12-8*0 Benzylide [C6H5CH2]- (g) 141.81 122.90 ± 0.43 kJ/mol 91.1310 ± 0.0056 18860-15-6*0 Ethylbenzene C6H5CH2CH3 (g) 58.17 29.70 ± 0.55 kJ/mol 106.1650 ± 0.0064 100-41-4*0 Phenylethene C6H5CHCH2 (g) 169.66 148.32 ± 0.55 kJ/mol 104.1491 ± 0.0064 100-42-5*0 Phenylacetylene C6H5CCH (g) 332.4 317.2 ± 1.1 kJ/mol 102.1332 ± 0.0064 536-74-3*0 Chlorodioxidanyl ClOO (g) 103.91 102.82 ± 0.37 kJ/mol 67.4515 ± 0.0011 17376-09-9*0 Acetonate [CH3C(O)CH2]- (g) -187.88 -201.43 ± 0.98 kJ/mol 57.0717 ± 0.0024 24262-31-5*0 Propadienone CH2CCO (g) 131.95 130.31 ± 0.79 kJ/mol 54.0474 ± 0.0024 61244-93-7*0 Nitrosomethane CH3NO (g) 81.3 71.4 ± 1.3 kJ/mol 45.04066 ± 0.00088 865-40-7*0 1-Cyanoethylidene CH3CCN (g, singlet) 475.6 470.4 ± 1.1 kJ/mol 53.0627 ± 0.0024 498544-34-6*2 3-Imino-2-propen-1-ylidene CHCHCNH (g, syn-singlet) 530.6 525.8 ± 1.2 kJ/mol 53.0627 ± 0.0024 916765-05-4*11 2-(Methylidyneamino)ethenyl CHCHNCH (g, anti-singlet) 600.6 595.5 ± 1.2 kJ/mol 53.0627 ± 0.0024 123416-74-0*11 1-Cyanovinyl anion [CH2CCN]- (g) 224.3 221.5 ± 1.3 kJ/mol 52.0553 ± 0.0024 36259-97-9*0 2-Cyanovinyl CHCHCN (g, anti) 447.9 445.5 ± 1.1 kJ/mol 52.0547 ± 0.0024 189141-20-6*1 Perchloryl OCl(O)O (g) 191.69 186.01 ± 0.61 kJ/mol 83.4509 ± 0.0013 13932-10-0*0 Nitroxyl ON(O)O (g) 79.40 74.14 ± 0.19 kJ/mol 62.00494 ± 0.00090 12033-49-7*0 Azanylium [NH3]+ (g) 944.272 937.317 ± 0.029 kJ/mol 17.03001 ± 0.00022 19496-55-0*0 Carbon cation C+ (g) 1797.850 1803.448 ± 0.047 kJ/mol 12.01015 ± 0.00080 14067-05-1*0 Methyliumylidene [CH]+ (g) 1619.755 1623.098 ± 0.053 kJ/mol 13.01809 ± 0.00080 24361-82-8*0 Ethylidyne CH3C (g, doublet) 508.51 504.81 ± 0.80 kJ/mol 27.0452 ± 0.0016 67624-57-1*1 Vinylidene anion [CCH2]- (g) 363.97 363.78 ± 0.50 kJ/mol 26.0378 ± 0.0016 66295-36-1*0 Hypochloroperoxoous acid, hydroxy ester HOOOCl (g, syn) 49.1 42.2 ± 1.9 kJ/mol 84.4588 ± 0.0013 928652-99-7*1 Cyanomethanide [CH2CN]- (g) 114.24 111.41 ± 0.69 kJ/mol 40.0446 ± 0.0016 21438-99-3*0 Iodine monobromide IBr (g) 49.718 40.771 ± 0.067 kJ/mol 206.8085 ± 0.0010 7789-33-5*0 Methanol cation [CH3OH]+ (g) 856.79 846.46 ± 0.32 kJ/mol 32.04131 ± 0.00090 12538-91-9*0 Methyloxonium [CH3OH2]+ (g) 588.5 574.3 ± 1.2 kJ/mol 33.04925 ± 0.00092 17836-08-7*0 Hydroxymethylene HCOH (g, gauche triplet) 219.3 216.4 ± 1.1 kJ/mol 30.02598 ± 0.00087 19710-56-6*3 Aquacarbon H2OC (g, triplet) 442.7 441.1 ± 1.3 kJ/mol 30.02598 ± 0.00087 81434-73-3*1 Hydroxyde [OH]- (aq) -230.014 ± 0.029 kJ/mol 17.00789 ± 0.00031 14280-30-9*800 Carbonic acid C(O)(OH)2 (g, cis-trans) -596.91 -607.02 ± 0.83 kJ/mol 62.0248 ± 0.0012 463-79-6*2 Carbonic acid C(O)(OH)2 (g, trans-trans) -561.68 -570.53 ± 0.97 kJ/mol 62.0248 ± 0.0012 463-79-6*3 Hydrogen carbonate [HOC(O)O]- (g) -720.6 -727.0 ± 1.4 kJ/mol 61.0174 ± 0.0012 71-52-3*0 n-Propylium [CH3CH2CH2]+ (g) 856.95 838.67 ± 0.85 kJ/mol 43.0871 ± 0.0024 19252-52-9*0 Dioxygen anion [O2]- (g) -43.36 -42.72 ± 0.17 kJ/mol 31.99935 ± 0.00060 11062-77-4*0 Propylidene CH3CH2CH (g, triplet) 349.44 335.75 ± 0.96 kJ/mol 42.0797 ± 0.0024 6700-78-3*1 Allyl anion [CH2CHCH2]- (g) 134.09 123.08 ± 0.23 kJ/mol 41.0723 ± 0.0024 1724-46-5*0 Cyclopropyl CH(CH2CH2) (g) 303.3 290.7 ± 1.3 kJ/mol 41.0718 ± 0.0024 2417-82-5*0 Propylidyne CH3CH2C (g, quartet) 624.5 613.0 ± 1.3 kJ/mol 41.0718 ± 0.0024 85056-54-8*2 1-Propynylide [CH3CC]- (g) 264.35 260.77 ± 0.70 kJ/mol 39.0565 ± 0.0024 36147-87-2*0 1-Propen-1-yl-3-ylidene CHCHCH (g, c-c quartet) 656.6 653.2 ± 1.1 kJ/mol 39.0559 ± 0.0024 84654-90-0*11 sec-Butyl CH3CH2CHCH3 (g) 90.86 66.09 ± 0.87 kJ/mol 57.1143 ± 0.0033 2348-55-2*0 Oxygen atom O (g, singlet) 436.666 438.523 ± 0.0021 kJ/mol 15.99940 ± 0.00030 17778-80-2*2 Oxirene O(CHCH) (g, t-triplet) 387.8 383.6 ± 1.4 kJ/mol 42.0367 ± 0.0016 157-18-6*11 Oxiranylidene CH2(CO) (g, singlet) 213.5 209.2 ± 1.4 kJ/mol 42.0367 ± 0.0016 50983-85-2*2 Dioxirane CH2(OO) (g) 9.40 1.74 ± 0.55 kJ/mol 46.0254 ± 0.0010 157-26-6*0 Hydroxyformyl anion [HOCO]- (g, trans) -313.63 -315.43 ± 0.58 kJ/mol 45.0180 ± 0.0010 78944-70-4*1 Ethoxyethene CH2CHOCH2CH3 (g, cis-trans) -117.7 -141.5 ± 1.5 kJ/mol 72.1057 ± 0.0033 109-92-2*2 Cyanic acid HOCN (g) -12.29 -15.00 ± 0.48 kJ/mol 43.02478 ± 0.00086 420-05-3*0 Isofulminic acid HONC (g) 235.29 233.58 ± 0.48 kJ/mol 43.02478 ± 0.00086 506-85-4*0 Acetic acid CH3C(O)OH (g) -418.86 -432.99 ± 0.42 kJ/mol 60.0520 ± 0.0017 64-19-7*0 Ethyl formate HC(O)OCH2CH3 (g, syn) -375.2 -393.9 ± 1.2 kJ/mol 74.0785 ± 0.0025 109-94-4*1 Methoxyoxomethyl CH3OCO (g, anti-staggered) -152.5 -160.6 ± 1.5 kJ/mol 59.0440 ± 0.0017 16481-04-2*1 (Formyloxy)methyl HC(O)OCH2 (g, syn) -151.9 -160.1 ± 1.3 kJ/mol 59.0440 ± 0.0017 3122-12-1*1 Ethylene glycol (CH2OH)2 (g) -369.75 -389.38 ± 0.40 kJ/mol 62.0678 ± 0.0018 107-21-1*0 Dioxoethyl OCHCO (g) -63.7 -65.1 ± 1.3 kJ/mol 57.0281 ± 0.0017 702699-38-5*0 (Methylamino)methyl cation [CH3NHCH2]+ (g) 729.05 710.43 ± 0.98 kJ/mol 44.0752 ± 0.0017 *31277-24-4*0 Diazomethyl HCNN (g) 470.6 468.1 ± 1.5 kJ/mol 41.03212 ± 0.00082 20813-32-5*0 Isocyanoamidogen HNNC (g) 491.1 489.1 ± 1.5 kJ/mol 41.03212 ± 0.00082 947408-73-3*0 Dichloromethyl CHCl2 (g) 92.20 90.28 ± 0.88 kJ/mol 83.9240 ± 0.0020 3474-12-2*0 Chloromethyl CH2Cl (g) 118.46 115.38 ± 0.87 kJ/mol 49.4793 ± 0.0012 6806-86-6*0 Methyl hypochlorite CH3OCl (g) -53.1 -63.0 ± 1.4 kJ/mol 66.4866 ± 0.0013 593-78-2*0 1,2-Dichloroethane CH2ClCH2Cl (g) -118.59 -130.53 ± 0.54 kJ/mol 98.9586 ± 0.0024 107-06-2*0 Trioxygen difluoride FOOOF (g, trans) 112.2 106.5 ± 1.1 kJ/mol 85.99501 ± 0.00090 16829-28-0*1 Ozonide [OOO]- (g) -58.48 -60.84 ± 0.21 kJ/mol 47.99875 ± 0.00090 12596-80-4*0 Chlorofluoromethane CH2FCl (g) -256.1 -263.3 ± 1.1 kJ/mol 68.4777 ± 0.0012 593-70-4*0 Difluoromethyliumyl [CF2]+ (g) 908.19 908.62 ± 0.78 kJ/mol 50.00696 ± 0.00080 54250-40-7*0 Trioxidanyl HOOO (g, trans) 25.32 23.33 ± 0.13 kJ/mol 49.00614 ± 0.00090 12500-78-6*1 Fluoromethyliumylidene [CF]+ (g) 1122.93 1126.14 ± 0.46 kJ/mol 31.00855 ± 0.00080 33412-11-2*0 1,2-Difluoroacetylene FCCF (g) 2.87 5.70 ± 0.65 kJ/mol 62.0182 ± 0.0016 689-99-6*0 Formyl chloride CHClO (g) -179.99 -183.20 ± 0.77 kJ/mol 64.4707 ± 0.0012 2565-30-2*0 Chloroformyl ClCO (g) -21.92 -20.53 ± 0.49 kJ/mol 63.4628 ± 0.0012 2602-42-8*0 Bromochlorane BrCl (g) 21.882 14.439 ± 0.060 kJ/mol 115.3567 ± 0.0013 13863-41-7*0 o-Benzyne anion [C6H4]- (g) 413.62 404.51 ± 0.96 kJ/mol 76.0965 ± 0.0048 100569-88-8*0 Oxidanylium [OH]+ (g) 1293.188 1293.217 ± 0.035 kJ/mol 17.00679 ± 0.00031 12259-29-9*0 Cycloheptene CH2(CHCHCH2CH2CH2CH2 (g) 28.17 -9.05 ± 0.75 kJ/mol 96.1702 ± 0.0057 628-92-2*0 Cycloheptatriene CH2(CHCHCHCHCHCH) (g) 207.10 183.67 ± 0.95 kJ/mol 92.1384 ± 0.0056 544-25-2*0 Dioxaziridinyl N(OO) (g) 355.1 352.6 ± 1.4 kJ/mol 46.00554 ± 0.00060 66252-29-7*0 Fluorobenzene cation [C6H5F]+ (g) 788.89 773.87 ± 0.89 kJ/mol 96.1018 ± 0.0048 34468-25-2*0 Nitrosobenzene C6H5NO (g) 215.7 198.8 ± 1.2 kJ/mol 107.1100 ± 0.0048 586-96-9*0 Nitromethyl CH2N(O)O (g) 138.9 129.5 ± 1.2 kJ/mol 60.0321 ± 0.0010 16787-85-2*0 2-Butanone CH3CH2C(O)CH3 (g) -217.02 -238.47 ± 0.79 kJ/mol 72.1057 ± 0.0033 78-93-3*0 Methylketene CH3CHCO (g) -54.7 -64.2 ± 1.1 kJ/mol 56.0633 ± 0.0024 6004-44-0*0 Acrolein CH2CHCHO (g, trans) -55.3 -65.7 ± 1.2 kJ/mol 56.0633 ± 0.0024 107-02-8*1 Formaldoxime CH2NOH (g, trans) 30.7 20.1 ± 1.4 kJ/mol 45.04066 ± 0.00088 75-17-2*1 Diazenyl NNH (g) 252.13 249.22 ± 0.45 kJ/mol 29.02142 ± 0.00016 36882-13-0*0 Fluoride F- (aq) -334.50 ± 0.16 kJ/mol 18.99895178 ± 0.00000050 16984-48-8*800 Hydroxyimidogen NOH (g) 217.84 214.95 ± 0.78 kJ/mol 31.01408 ± 0.00032 35337-59-8*0 Peroxynitric acid HOON(O)O (g) -42.6 -52.9 ± 1.3 kJ/mol 79.0123 ± 0.0012 26404-66-0*0 Nitrosyl chloride ClNO (g) 54.453 52.552 ± 0.067 kJ/mol 65.45884 ± 0.00095 2696-92-6*0 Carbon dioxide CO2 (g, triplet) 49.8 50.6 ± 1.1 kJ/mol 44.00950 ± 0.00100 124-38-9*1 Methane cation [CH4]+ (g) 1150.670 1144.287 ± 0.062 kJ/mol 16.04191 ± 0.00085 20741-88-2*0 Oxygen atom O (g, triplet) 246.844 249.229 ± 0.0021 kJ/mol 15.99940 ± 0.00030 17778-80-2*1 Ethanium [C2H7]+ (g) 874.32 858.08 ± 0.62 kJ/mol 31.0764 ± 0.0017 24669-33-8*0 Acetylene cation [HCCH]+ (g) 1328.83 1328.17 ± 0.13 kJ/mol 26.0367 ± 0.0016 25641-79-6*0 1-Ethylium-1-ylidene [CH3C]+ (g) 1329.6 1328.2 ± 1.2 kJ/mol 27.0447 ± 0.0016 78949-84-5*0 Ethylidyne anion [CH3C]- (g) 457.0 452.9 ± 1.2 kJ/mol 27.0458 ± 0.0016 117768-70-4*0 Water anion [(H)(OH)]- (g, vdW ?) 31.3 29.8 ± 3.1 kJ/mol 18.01583 ± 0.00033 12259-30-2*100 Isocyanomethyl CH2NC (g) 363.6 361.1 ± 1.2 kJ/mol 40.0440 ± 0.0016 70971-59-4*0 Trioxidanylium [HOOO]+ (g, trans) 1070.4 1064.1 ± 1.4 kJ/mol 49.00559 ± 0.00090 74241-49-9*1 Methyloxoniumylidene [CH3O]+ (g) 1062.68 1054.87 ± 0.75 kJ/mol 31.03337 ± 0.00088 58157-09-8*0 Chlorine difluoride FClF (g) -47.0 -48.2 ± 1.4 kJ/mol 73.44951 ± 0.00090 24801-48-7*0 Hydroxymethylene HCOH (g, cis) 131.09 127.35 ± 0.29 kJ/mol 30.02598 ± 0.00087 19710-56-6*2 Hydroxymethylene cation [HCOH]+ (g, trans) 971.9 968.2 ± 1.4 kJ/mol 30.02543 ± 0.00087 135395-06-1*1 Isoformyl COH (g) 217.25 217.64 ± 0.69 kJ/mol 29.01804 ± 0.00086 71080-92-7*0 1-Methylethylidene CH3CCH3 (g, triplet) 326.8 313.6 ± 1.2 kJ/mol 42.0797 ± 0.0024 40852-89-9*1 Allylium [CH2CHCH2]+ (g) 964.53 952.97 ± 0.44 kJ/mol 41.0713 ± 0.0024 1724-44-3*0 1-Propenyl CH3CHCH (g, trans) 280.32 269.49 ± 0.81 kJ/mol 41.0718 ± 0.0024 6067-68-1*1 Cycloprop-1-enyl CH2(CHC) (g) 527.40 523.01 ± 0.61 kJ/mol 39.0559 ± 0.0024 19528-44-0*0 Cycloprop-2-enylium [CH(CHCH)]+ (g) 1080.3 1075.2 ± 1.1 kJ/mol 39.0554 ± 0.0024 26810-74-2*0 Cyclopropynyl CH(CC) (g) 710.96 715.08 ± 0.85 kJ/mol 37.0400 ± 0.0024 119178-99-3*0 n-Butyl anion [CH3CH2CH2CH2]- (g) 105.8 80.9 ± 1.3 kJ/mol 57.1148 ± 0.0033 79431-01-9*0 sec-Butyl anion [CH3CH2CHCH3]- (g) 103.0 78.5 ± 1.3 kJ/mol 57.1148 ± 0.0033 79431-00-8*0 Cyclopentene CH2(CH2CHCHCH2) (g) 59.46 35.19 ± 0.45 kJ/mol 68.1170 ± 0.0040 142-29-0*0 n-Heptane CH3(CH2)5CH3 (g) -145.65 -187.52 ± 0.48 kJ/mol 100.2019 ± 0.0057 142-82-5*0 n-Octane CH3(CH2)6CH3 (g) -161.42 -208.25 ± 0.67 kJ/mol 114.2285 ± 0.0065 111-65-9*0 1-Hydroxyethylium [CH3CHOH]+ (g, syn) 610.9 596.4 ± 1.1 kJ/mol 45.0600 ± 0.0017 18682-96-7*2 Vinyl alcohol cation [CH2CHOH]+ (g, anti) 778.7 767.4 ± 1.3 kJ/mol 44.0520 ± 0.0017 57239-63-1*2 Oxiranyl CH2(CHO) (g) 172.5 164.2 ± 1.3 kJ/mol 43.0446 ± 0.0016 31586-84-2*0 Oxiranylium [CH2(CHO)]+ (g, singlet) 901.1 893.2 ± 1.5 kJ/mol 43.0441 ± 0.0016 57789-76-1*2 Hydrogen chloride HCl (aq, 100 H2O) -165.757 ± 0.025 kJ/mol 36.46064 ± 0.00090 7647-01-0*828 C=O=C COC (g, triplet) 653.0 657.3 ± 1.5 kJ/mol 40.0208 ± 0.0016 *12071-23-7*1 C=O=C COC (g, singlet) 721.9 726.2 ± 1.6 kJ/mol 40.0208 ± 0.0016 *12071-23-7*2 Bromide Br- (aq) -120.65 ± 0.15 kJ/mol 79.90455 ± 0.00100 24959-67-9*800 Oxoethylidene HCC(O)H (g, singlet) 275.4 272.6 ± 1.7 kJ/mol 42.0367 ± 0.0016 39920-84-8*2 Ethyl hydroperoxide CH3CH2OOH (g) -143.2 -161.6 ± 1.2 kJ/mol 62.0678 ± 0.0018 3031-74-1*0 Hydrogen fluoride HF (aq, 30 H2O) -321.10 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*820 Formic acid cation [HC(O)OH]+ (g, syn) 721.87 714.78 ± 0.26 kJ/mol 46.0248 ± 0.0010 50614-05-6*1 Azide [NNN]- (g) 193.55 190.04 ± 0.91 kJ/mol 42.02077 ± 0.00021 14343-69-2*0 Formyloxidanyl HC(O)O (g, 2B2) -122.10 -125.45 ± 0.56 kJ/mol 45.0174 ± 0.0010 16499-21-1*2 Chloryl hydride HCl(O)O (g) 197.6 191.2 ± 1.6 kJ/mol 68.4594 ± 0.0011 174365-32-3*0 Dinitrogen pentoxide O2NONO2 (g) 24.43 14.86 ± 0.35 kJ/mol 108.0105 ± 0.0015 10102-03-1*0 1-Propanol CH3CH2CH2OH (g) -231.41 -255.26 ± 0.25 kJ/mol 60.0950 ± 0.0025 71-23-8*0 Fulminic acid HCNO (g) 170.83 169.37 ± 0.49 kJ/mol 43.02478 ± 0.00086 51060-05-0*0 Hydrogen difluoride (F)(HF) (g, lin) -198.5 -198.4 ± 1.2 kJ/mol 39.004746 ± 0.000070 12528-21-1*1 (Formyloxy)methyl HC(O)OCH2 (g, anti) -136.3 -144.5 ± 1.3 kJ/mol 59.0440 ± 0.0017 3122-12-1*2 Carboxymethyl CH2C(O)OH (g, anti) -206.7 -216.0 ± 1.3 kJ/mol 59.0440 ± 0.0017 2887-46-9*2 Dimethylamide [(CH3)2N]- (g) 122.2 103.8 ± 1.7 kJ/mol 44.0763 ± 0.0017 34285-60-4*0 Oxoniumyl ion [H2O]+ (g) 978.467 975.564 ± 0.028 kJ/mol 18.01473 ± 0.00033 56583-62-1*0 Iodide I- (aq) -56.824 ± 0.090 kJ/mol 126.905019 ± 0.000030 20461-54-5*800 1H-Triazirin-1-yl N(NN) (g) 585.9 584.1 ± 2.0 kJ/mol 42.02022 ± 0.00021 912535-95-6*0 1,1,2-Trichloroethane CH2ClCHCl2 (g) -136.6 -148.3 ± 1.4 kJ/mol 133.4033 ± 0.0031 79-00-5*0 1,1,1,2-Tetrachloroethane CH2ClCCl3 (g) -144.5 -153.1 ± 1.3 kJ/mol 167.8481 ± 0.0039 630-20-6*0 Pentachloroethyl CCl3CCl2 (g) 27.0 25.1 ± 1.3 kJ/mol 201.2849 ± 0.0048 7094-17-9*0 Iodomethane CH3I (l) -12.17 ± 0.20 kJ/mol 141.93899 ± 0.00083 74-88-4*590 Difluoromethylene CF2 (g, triplet) 43.29 44.00 ± 0.38 kJ/mol 50.00751 ± 0.00080 2154-59-8*1 Ethyl iodide CH3CH2I (l) -9.41 -39.28 ± 0.49 kJ/mol 155.9656 ± 0.0016 75-03-6*500 cis-1,2-Difluoroethene CHFCHF (g, cis) -302.90 -309.66 ± 0.90 kJ/mol 64.0341 ± 0.0016 1630-77-9*0 Fluoroethynyl CCF (g) 445.2 449.8 ± 1.6 kJ/mol 43.0198 ± 0.0016 22533-50-2*0 Fluoro(fluorooxy)methylene FCOF (g, cis) -134.8 -136.0 ± 1.3 kJ/mol 66.00691 ± 0.00085 479587-30-9*2 Dibromophosgene CBr2O (g) -97.96 -113.89 ± 0.37 kJ/mol 187.8181 ± 0.0022 593-95-3*0 Benzene C6H6 (cr,l) 50.71 49.16 ± 0.23 kJ/mol 78.1118 ± 0.0048 71-43-2*500 o-Benzyne C6H4 (g) 468.00 459.09 ± 0.87 kJ/mol 76.0960 ± 0.0048 462-80-6*0 m-Benzyne C6H4 (g, singlet) 526.9 518.4 ± 1.2 kJ/mol 76.0960 ± 0.0048 1828-89-3*2 p-Benzyne C6H4 (g, singlet) 586.9 577.4 ± 1.2 kJ/mol 76.0960 ± 0.0048 3355-34-8*2 Cycloheptane CH2(CH2CH2CH2CH2CH2C (g) -72.76 -118.26 ± 0.53 kJ/mol 98.1861 ± 0.0057 291-64-5*0 Dioxidenium [HO2]+ (g) 1110.87 1107.98 ± 0.11 kJ/mol 33.00619 ± 0.00060 12207-52-2*0 Benzoyl fluoride C6H5C(O)F (g) -288.1 -304.5 ± 1.5 kJ/mol 124.1124 ± 0.0056 455-32-3*0 Iodine cation I+ (g) 1115.549 1115.149 ± 0.0062 kJ/mol 126.903921 ± 0.000030 22541-93-1*0 Bifluoride [(HF)(F)]- (g, singlet) -481.7 -480.6 ± 1.9 kJ/mol 39.005295 ± 0.000070 *18130-74-0*2 2-Cyclopropen-1-one OC(CHCH) (g) 163.7 159.8 ± 1.2 kJ/mol 54.0474 ± 0.0024 2961-80-0*0 Cyanovinylidene CCHCN (g) 581.6 584.1 ± 1.2 kJ/mol 51.0468 ± 0.0024 70277-81-5*0 Isocyanovinylidene CCHNC (g) 696.8 700.1 ± 1.4 kJ/mol 51.0468 ± 0.0024 737788-76-0*0 Cyanoacetylide [CCCN]- (g) 300.2 305.5 ± 1.2 kJ/mol 50.0394 ± 0.0024 12373-53-4*0 Isocyanoethene CH2CHNC (g, singlet) 285.02 278.51 ± 0.95 kJ/mol 53.0627 ± 0.0024 14668-82-7*1 1-Cyanoethylidene CH3CCN (g, triplet) 437.5 433.7 ± 1.5 kJ/mol 53.0627 ± 0.0024 498544-34-6*1 Isocyanomethylene HCNC (g, singlet) 582.3 583.6 ± 1.7 kJ/mol 39.0361 ± 0.0016 78694-65-2*1 Propargyl chloride HCCCH2Cl (g) 186.5 180.6 ± 1.3 kJ/mol 74.5086 ± 0.0026 624-65-7*0 Silicon Si (g) 446.23 450.57 ± 0.20 kJ/mol 28.08550 ± 0.00030 7440-21-3*0 Dioxiranylidene C(OO) (g) 190.3 191.1 ± 1.4 kJ/mol 44.00950 ± 0.00100 138832-57-2*0 Methylidyne CH (g, doublet) 592.820 596.154 ± 0.098 kJ/mol 13.01864 ± 0.00080 3315-37-5*1 Fluorohydrochlorine cation [FClH]+ (g) 975.3 972.3 ± 2.0 kJ/mol 55.45849 ± 0.00090 70110-64-4*0 Oxofluoronium [FO]+ (g) 1342.65 1342.60 ± 0.81 kJ/mol 34.99725 ± 0.00030 12763-67-6*0 Chlorine fluoride cation [ClF]+ (g) 1165.53 1165.71 ± 0.49 kJ/mol 54.45055 ± 0.00090 12432-44-9*0 Methylammonium [CH3NH3]+ (g) 628.4 609.5 ± 1.4 kJ/mol 32.06453 ± 0.00091 17000-00-9*0 Aminomethylene CHNH2 (g) 245.9 238.2 ± 1.5 kJ/mol 29.04126 ± 0.00083 35430-17-2*0 Methylimidogen CH3N (g) 323.1 315.3 ± 1.1 kJ/mol 29.04126 ± 0.00083 27770-42-9*0 Methyleneamidogen anion [CH2N]- (g) 192.77 189.01 ± 0.91 kJ/mol 28.03387 ± 0.00082 28892-56-0*0 (Z)-Iminomethyl HCNH (g, cis) 294.50 291.01 ± 0.90 kJ/mol 28.03332 ± 0.00082 54980-11-9*0 Aminomethylidyne CNH2 (g) 371.9 368.4 ± 1.1 kJ/mol 28.03332 ± 0.00082 84654-89-7*0 Peroxychlorous acid HOOClO (g, syn) 96.2 90.2 ± 2.1 kJ/mol 84.4588 ± 0.0013 177778-92-6*1 Deuterium atom D (g) 219.804 221.717 ± 0.000 kJ/mol 2.01410177800 ± 0.00000000040 16873-17-9*0 Methyleneoxonium CH2OH2 (g) 152.44 144.12 ± 0.49 kJ/mol 32.04186 ± 0.00090 177788-17-9*0 (Z)-Diazene HNNH (g, cis) 228.81 221.67 ± 0.63 kJ/mol 30.02936 ± 0.00020 15626-42-3*0 Hydroxymethylene anion [HCOH]- (g, trans) 147.1 144.1 ± 1.6 kJ/mol 30.02653 ± 0.00087 207914-87-2*1 Chlorine difluoride cation [FClF]+ (g) 998.9 996.7 ± 1.7 kJ/mol 73.44896 ± 0.00090 32629-46-2*0 Hydroxymethyliumylidene [COH]+ (g) 986.02 987.65 ± 0.83 kJ/mol 29.01749 ± 0.00086 60528-75-8*0 Isoformyl anion [(CO)(H)]- (g, vdW singlet ?) 55.7 58.4 ± 1.8 kJ/mol 29.01859 ± 0.00086 81747-63-9*1 Peroxyformic acid HC(O)OOH (g, trans) -265.4 -273.3 ± 1.6 kJ/mol 62.0248 ± 0.0012 107-32-4*2 Hydroxyoxomethoxy HOC(O)O (g) -358.9 -365.0 ± 1.5 kJ/mol 61.0168 ± 0.0012 38330-85-7*0 Hydroperoxycarbonyl HOOCO (g) -73.0 -76.8 ± 1.7 kJ/mol 61.0168 ± 0.0012 153751-35-0*0 Nitrosodioxaziridine ONN(OO) (g, trans) 413.6 407.6 ± 1.8 kJ/mol 76.01168 ± 0.00091 132871-99-9*1 Trioxidaniumyl [HOOOH]+ (g, t, t) 925.5 916.2 ± 1.5 kJ/mol 50.01353 ± 0.00091 161321-37-5*2 Oxywater (H2O)O (g) 64.8 58.3 ± 1.3 kJ/mol 34.01468 ± 0.00062 171363-09-0*0 Perchloric acid HOCl(O)(O)O (g) 13.2 1.8 ± 1.8 kJ/mol 100.4582 ± 0.0015 7601-90-3*0 Dinitrogen tetraoxide O2NNO2 (g) 20.15 10.86 ± 0.14 kJ/mol 92.0111 ± 0.0012 10544-72-6*0 Propan-1-yl-3-ylidene CH2CH2CH (g, quartet) 554.2 545.6 ± 1.3 kJ/mol 41.0718 ± 0.0024 *50457-59-5*2 1-Propenylidene CH3CHC (g, singlet) 392.3 388.0 ± 1.1 kJ/mol 40.0639 ± 0.0024 70277-78-0*1 1-Propynyl CH3CC (g) 528.30 526.12 ± 0.70 kJ/mol 39.0559 ± 0.0024 89342-91-6*0 Hydroxyaminiumyl [NOH]+ (g) 1161.1 1158.2 ± 1.4 kJ/mol 31.01353 ± 0.00032 63559-88-6*0 Cycloprop-2-enyl CH(CHCH) (g) 490.22 485.67 ± 0.60 kJ/mol 39.0559 ± 0.0024 28933-84-8*0 2-Propen-1-yl-3-ylidene CH2CHC (g) 556.56 554.30 ± 0.90 kJ/mol 39.0559 ± 0.0024 202744-74-9*0 Cyclopropenylidene C(CHCH) (g) 497.03 496.07 ± 0.46 kJ/mol 38.0480 ± 0.0024 16165-40-5*0 2-Propynylidyne anion [CCCH]- (g) 540.01 544.79 ± 0.83 kJ/mol 37.0406 ± 0.0024 82893-67-2*0 t-Butylium [(CH3)3C]+ (g) 733.76 710.48 ± 0.98 kJ/mol 57.1137 ± 0.0033 14804-25-2*0 t-Butyl anion [(CH3)3C]- (g) 76.1 51.3 ± 1.5 kJ/mol 57.1148 ± 0.0033 65114-21-8*0 iso-Butyl (CH3)2CHCH2 (g) 96.91 72.92 ± 0.92 kJ/mol 57.1143 ± 0.0033 4630-45-9*0 Methylcyclopropane CH3CH(CH2CH2) (g) 47.8 24.5 ± 1.3 kJ/mol 56.1063 ± 0.0032 594-11-6*0 Ethanol CH3CH2OH (l) -269.75 -277.51 ± 0.22 kJ/mol 46.0684 ± 0.0017 64-17-5*500 2-Hydroxyethyl CH2CH2OH (g, staggered-anti) -5.5 -17.9 ± 1.3 kJ/mol 45.0605 ± 0.0017 4422-54-2*3 Hydroxyamidogen HNOH (g, cis) 123.4 116.8 ± 1.7 kJ/mol 32.02202 ± 0.00034 13940-32-4*2 Vinyl alcohol cation [CH2CHOH]+ (g, syn) 786.75 775.52 ± 0.85 kJ/mol 44.0520 ± 0.0017 57239-63-1*1 Vinoxy cation [CH2CHO]+ (g, triplet) 1020.1 1013.1 ± 1.5 kJ/mol 43.0441 ± 0.0016 *35731-40-9*1 Vinoxide [CH2CHO]- (g) -153.04 -160.10 ± 0.68 kJ/mol 43.0452 ± 0.0016 35731-40-9*0 2-Hydroxyethenyl CHCHOH (g, trans-cis) 138.01 131.27 ± 0.92 kJ/mol 43.0446 ± 0.0016 108665-16-3*21 Hydroxyaminylium [HNOH]+ (g, trans) 1019.5 1012.4 ± 2.5 kJ/mol 32.02147 ± 0.00034 66097-71-0*1 Oxiranyl anion [CH2(CHO)]- (g, singlet) 121.2 113.2 ± 1.5 kJ/mol 43.0452 ± 0.0016 72722-59-9*2 Acetic acid CH3C(O)OH (aq) -485.18 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*800 Ketene CH2CO (g, singlet) -45.35 -48.47 ± 0.11 kJ/mol 42.0367 ± 0.0016 463-51-4*2 COC vdW (CO)(C) (g, triplet) 589.7 598.5 ± 1.5 kJ/mol 40.0208 ± 0.0016 *12071-24-8*1 Oxirene O(CHCH) (g, c-triplet) 389.8 385.7 ± 1.4 kJ/mol 42.0367 ± 0.0016 157-18-6*12 Bifluoride [FFH]- (g, triplet) -68.0 -67.6 ± 1.6 kJ/mol 39.005295 ± 0.000070 *18130-74-0*1 Formyloxoniumylidene [HC(O)O]+ (g) 1017.3 1013.9 ± 1.4 kJ/mol 45.0169 ± 0.0010 54375-27-8*0 Dioxymethylene HCOO (g, trans) 364.0 361.7 ± 2.4 kJ/mol 45.0174 ± 0.0010 438586-67-5*1 2-Propanol CH3CH(OH)CH3 (g) -249.42 -273.52 ± 0.36 kJ/mol 60.0950 ± 0.0025 67-63-0*0 Dihydrogen fluoride anion [HFH]- (g, triplet) 133.2 131.9 ± 1.6 kJ/mol 21.01483 ± 0.00014 117339-92-1*1 Cyanate [NCO]- (g) -221.21 -221.43 ± 0.53 kJ/mol 42.01739 ± 0.00086 661-20-1*0 Nitrosomethylidyne CNO (g) 388.8 390.2 ± 1.4 kJ/mol 42.01684 ± 0.00086 82267-15-0*0 Oxazirinyl C(NO) (g) 450.0 450.7 ± 1.5 kJ/mol 42.01684 ± 0.00086 228850-18-8*0 Propionic acid CH3CH2C(O)OH (g, syn) -436.41 -454.31 ± 0.60 kJ/mol 74.0785 ± 0.0025 79-09-4*1 2-Methoxy-2-oxoethyl CH2C(O)OCH3 (g, syn) -203.4 -218.7 ± 1.6 kJ/mol 73.0706 ± 0.0025 54668-31-4*1 (Acetyloxy)methyl CH3C(O)OCH2 (g, syn) -200.7 -214.5 ± 1.6 kJ/mol 73.0706 ± 0.0025 2887-49-2*1 Dimethylmethyleneammonium [(CH3)2NCH2]+ (g) 696.4 671.3 ± 1.4 kJ/mol 58.1018 ± 0.0025 28149-27-1*0 Hydrogen fluoride HF (aq, 40 H2O) -321.13 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*821 Trichloromethide [CCl3]- (g) -124.8 -124.3 ± 2.0 kJ/mol 118.3693 ± 0.0028 14478-07-0*0 2-Hydrotrioxy cation [OO(H)O]+ (g) 1298.2 1291.5 ± 1.5 kJ/mol 49.00559 ± 0.00090 *74241-49-9*0 Dioxyamidogen HNOO (g, cis) 240.4 233.8 ± 1.8 kJ/mol 47.01348 ± 0.00061 71843-95-3*2 1,1,2,2-Tetrachloroethane CHCl2CHCl2 (g) -146.9 -156.2 ± 1.5 kJ/mol 167.8481 ± 0.0039 79-34-5*0 1,1,2,2-Tetrachloroethane CHCl2CHCl2 (cr,l) -173.0 -202.0 ± 1.5 kJ/mol 167.8481 ± 0.0039 79-34-5*500 Pentachloroethane CHCl2CCl3 (cr,l) -202.9 ± 2.5 kJ/mol 202.2928 ± 0.0048 76-01-7*500 Trichloroethene CHClCCl2 (l) -49.2 ± 1.5 kJ/mol 131.3874 ± 0.0031 79-01-6*590 Tetrachloroethene CCl2CCl2 (l) -62.9 ± 1.1 kJ/mol 165.8322 ± 0.0039 127-18-4*500 Chlorine chlorite ClOClO (g, gauche) 168.6 166.2 ± 1.3 kJ/mol 102.9042 ± 0.0019 105206-44-8*3 Trichloroethene CHClCCl2 (g) -11.3 -14.6 ± 1.5 kJ/mol 131.3874 ± 0.0031 79-01-6*0 2-Hydrotrioxy anion [OO(H)O]- (g) 27.5 21.8 ± 1.4 kJ/mol 49.00669 ± 0.00090 *89965-38-8*0 Triiodide [I3]- (aq) -51.41 ± 0.80 kJ/mol 380.713959 ± 0.000090 14900-04-0*800 Bromodichloromethane CHCl2Br (g) -37.4 -49.1 ± 1.2 kJ/mol 163.8280 ± 0.0022 75-27-4*0 Oxygen cation monohydrate [(HOH)O]+ (g) 1153.3 1147.8 ± 3.3 kJ/mol 34.01413 ± 0.00062 *31748-17-1*0 Difluorodibromomethane CF2Br2 (g) -364.0 -382.0 ± 1.3 kJ/mol 209.8155 ± 0.0022 75-61-6*0 Dichlorodibromomethane CCl2Br2 (g) 21.0 5.1 ± 1.3 kJ/mol 242.7241 ± 0.0028 594-18-3*0 Difluorobromomethane CHF2Br (g) -411.08 -424.28 ± 0.47 kJ/mol 130.9194 ± 0.0013 1511-62-2*0 Chlorosyl hydride HClO (g) 141.9 139.1 ± 1.7 kJ/mol 52.46004 ± 0.00095 71572-35-5*0 1,2-Difluoroethane CH2FCH2F (g) -434.40 -447.82 ± 0.81 kJ/mol 66.0500 ± 0.0016 624-72-6*0 Fluoro(fluorooxy)methylene FCOF (g, trans) -37.5 -39.1 ± 1.4 kJ/mol 66.00691 ± 0.00085 479587-30-9*1 Aquachlorine cation [ClOH2]+ (g) 821.8 815.0 ± 1.7 kJ/mol 53.46743 ± 0.00096 142599-65-3*0 Phenylium [C6H5]+ (g, triplet) 1250.6 1237.6 ± 1.6 kJ/mol 77.1034 ± 0.0048 17333-73-2*1 Peroxynitrous acid HOONO (g, cis, perp) -0.19 -7.24 ± 0.53 kJ/mol 63.01288 ± 0.00091 14691-52-2*2 Hydrogen difluoride cation [FFH]+ (g) 1174.3 1171.3 ± 1.5 kJ/mol 39.004198 ± 0.000070 *126950-54-7*0 Chlorobenzene cation [C6H5Cl]+ (g) 942.47 928.55 ± 0.61 kJ/mol 112.5561 ± 0.0049 55450-32-3*0 Chlorobenzene C6H5Cl (cr,l) 11.23 ± 0.59 kJ/mol 112.5566 ± 0.0049 108-90-7*500 m-Chlorophenyl C6H4Cl (g) 319.9 309.1 ± 1.6 kJ/mol 111.5487 ± 0.0049 3474-40-6*0 p-Chlorophenyl C6H4Cl (g) 322.8 312.0 ± 1.6 kJ/mol 111.5487 ± 0.0049 2396-00-1*0 o-Chlorophenyl C6H4Cl (g) 327.2 316.4 ± 1.6 kJ/mol 111.5487 ± 0.0049 3474-42-8*0 Bromobenzene cation [C6H5Br]+ (g) 994.8 973.2 ± 1.3 kJ/mol 157.0074 ± 0.0049 55450-33-4*0 Iodobenzene C6H5I (cr,l) 112.8 112.9 ± 1.1 kJ/mol 204.0084 ± 0.0048 591-50-4*500 Oxygen anion monohydrate [(HOH)O]- (g) -239.0 -244.3 ± 3.0 kJ/mol 34.01523 ± 0.00062 31748-17-1*0 Nitrobenzene C6H5N(O)O (g) 81.4 61.4 ± 1.4 kJ/mol 123.1094 ± 0.0049 98-95-3*0 Methyl nitrite CH3ONO (g) -55.68 -66.35 ± 0.46 kJ/mol 61.0401 ± 0.0010 624-91-9*0 1,3-Butadien-2-ol CH2C(OH)CHCH2 (g, s-trans, syn) -53.9 -70.8 ± 1.6 kJ/mol 70.0898 ± 0.0032 59120-04-6*11 (E)-Diazene cation [HNNH]+ (g, trans) 1132.46 1125.52 ± 0.64 kJ/mol 30.02881 ± 0.00020 59952-06-6*0 Formaldonitrone CH2NHO (g) 78.6 67.3 ± 1.5 kJ/mol 45.04066 ± 0.00088 67353-84-8*0 2-Cyclopropen-1-imine (CHCH)CNH (g) 401.8 394.1 ± 1.4 kJ/mol 53.0627 ± 0.0024 31589-17-0*0 1-Isocyanovinyl CH2CNC (g) 519.0 517.2 ± 1.4 kJ/mol 52.0547 ± 0.0024 321850-14-0*0 Silicon carbide SiC (cr, alpha-hex) -71.0 -72.1 ± 1.4 kJ/mol 40.09620 ± 0.00085 409-21-2*501 Tetrafluorosilane SiF4 (g) -1609.28 -1614.79 ± 0.69 kJ/mol 104.07911 ± 0.00030 7783-61-1*0 Iminomethyl anion [HCNH]- (g, trans) 237.3 233.5 ± 1.8 kJ/mol 28.03387 ± 0.00082 90623-30-6*1 Chlorohydrofluorine cation [ClFH]+ (g) 1000.8 998.1 ± 2.1 kJ/mol 55.45849 ± 0.00090 70110-63-3*0 Dioxymethylidyne COO (g) 299.8 301.1 ± 1.7 kJ/mol 44.00950 ± 0.00100 791121-04-5*0 Diazenide [NNH]- (g, vdW) 175.6 176.7 ± 1.6 kJ/mol 29.02197 ± 0.00016 71004-29-0*100 Cyanogen iodide anion [ICN]- (g) 86.5 88.9 ± 8.1 kJ/mol 152.92246 ± 0.00080 1356929-44-6*0 Methanol CH3OH (l) -235.31 -238.64 ± 0.16 kJ/mol 32.04186 ± 0.00090 67-56-1*500 Formaldehyde cation [CH2O]+ (g) 944.864 941.243 ± 0.098 kJ/mol 30.02543 ± 0.00087 54288-05-0*0 Iodine I (g, 2P3/2) 107.157 106.757 ± 0.0021 kJ/mol 126.904470 ± 0.000030 14362-44-8*1 Isoformyl anion [COH]- (g, triplet) 267.4 268.0 ± 1.6 kJ/mol 29.01859 ± 0.00086 81747-63-9*2 Fluoronium [HFH]+ (g) 774.11 771.17 ± 0.88 kJ/mol 21.01373 ± 0.00014 12206-67-6*0 Hydrogen fluoride HF (aq, 35 H2O) -321.12 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*904 Carbide [C2]- (g) 504.74 511.31 ± 0.39 kJ/mol 24.0219 ± 0.0016 12595-78-7*0 2-Propenylidene CHCHCH2 (g, triplet anti) 417.4 409.9 ± 1.5 kJ/mol 40.0639 ± 0.0024 19527-08-3*11 2-Propenylidene CHCHCH2 (g, singlet) 452.59 445.45 ± 0.91 kJ/mol 40.0639 ± 0.0024 19527-08-3*2 Fluoronium [(HF)(H)]+ (g, triplet) 1490.1 1491.5 ± 1.9 kJ/mol 21.01373 ± 0.00014 12206-67-6*1 2-Cyclopropyn-1-ylidene C(CC) (g, triplet) 898.9 905.8 ± 1.6 kJ/mol 36.0321 ± 0.0024 102508-15-6*1 2-Cyclopropyn-1-ylium-1-yl [C(CC)]+ (g) 1944.7 1952.6 ± 1.9 kJ/mol 36.0316 ± 0.0024 154702-35-9*0 2-Cyclopropen-1-ylium-1-yl [C(CHCH)]+ (g) 1382.0 1380.9 ± 1.1 kJ/mol 38.0474 ± 0.0024 85398-75-0*0 Propynylidene HCCCH (g, cis singlet) 597.6 599.3 ± 1.3 kJ/mol 38.0480 ± 0.0024 67152-18-5*3 Propenediylidene CHCHC (g) 796.1 797.3 ± 1.4 kJ/mol 38.0480 ± 0.0024 60731-11-5*0 n-Butylium [CH3CH2CH2CH2]+ (g) 827.5 803.1 ± 1.2 kJ/mol 57.1137 ± 0.0033 25453-90-1*0 Dihydrogen fluoride anion [(F)(HH)]- (g, singlet) -257.0 -260.1 ± 1.9 kJ/mol 21.01483 ± 0.00014 *117339-92-1*2 Dibromide [Br2]- (g) -199.2 -213.3 ± 2.0 kJ/mol 159.8085 ± 0.0020 12595-70-9*0 Dioxygenyl ion monohydrate [(H2O)(O2)]+ (g) 828.5 821.4 ± 2.1 kJ/mol 50.01353 ± 0.00091 11083-61-7*0 iso-Hexane CH3CH2CH2CH(CH3)2 (g) -134.65 -173.91 ± 0.84 kJ/mol 86.1754 ± 0.0049 107-83-5*0 Ethyloxoniumyl [CH3CH2OH]+ (g) 783.3 766.3 ± 1.7 kJ/mol 46.0679 ± 0.0017 34480-55-2*0 1-Hydroxyethylium [CH3CHOH]+ (g) 608.75 594.32 ± 0.39 kJ/mol 45.0600 ± 0.0017 18682-96-7*0 2-Hydroxyethylium [CH2CH2OH]+ (g, staggered-anti) 1019.1 1006.3 ± 1.5 kJ/mol 45.0600 ± 0.0017 38607-31-7*3 Chloride Cl- (aq) -166.991 ± 0.023 kJ/mol 35.45325 ± 0.00090 16887-00-6*800 Ethyloxoniumylidene [CH3CH2O]+ (g) 988.7 975.0 ± 1.5 kJ/mol 45.0600 ± 0.0017 54387-07-4*0 Acetaldehyde cation [CH3CHO]+ (g) 831.91 821.93 ± 0.26 kJ/mol 44.0520 ± 0.0017 36505-03-0*0 Oxiranylium [CH2(CHO)]+ (g, triplet) 1233.4 1226.4 ± 1.7 kJ/mol 43.0441 ± 0.0016 57789-76-1*1 Oxiranyl anion [CH2(CHO)]- (g, triplet) 140.9 134.9 ± 1.6 kJ/mol 43.0452 ± 0.0016 72722-59-9*1 Peroxychlorite [OClOO]- (g) -34.3 -34.3 ± 2.0 kJ/mol 83.4514 ± 0.0013 852472-63-0*0 Ketenyl anion [HCCO]- (g) -48.48 -47.55 ± 0.82 kJ/mol 41.0293 ± 0.0016 64066-01-9*0 Dicarbon monoxide anion [CCO]- (g) 154.18 157.82 ± 0.83 kJ/mol 40.0213 ± 0.0016 87191-88-6*0 Dicarbon monoxide CCO (g, singlet) 440.22 444.55 ± 0.83 kJ/mol 40.0208 ± 0.0016 12071-23-7*2 Fluorochlorate [ClF]- (g) -256.02 -255.42 ± 0.81 kJ/mol 54.45165 ± 0.00090 12272-56-9*0 COC vdW (CO)(C) (g, singlet) 726.2 734.6 ± 1.7 kJ/mol 40.0208 ± 0.0016 *12071-24-8*2 C=O-C cation [COC]+ (g, doublet) 1585.8 1592.9 ± 2.7 kJ/mol 40.0203 ± 0.0016 83483-98-1*1 C=O=C anion [COC]- (g) 550.3 554.1 ± 1.7 kJ/mol 40.0213 ± 0.0016 *87191-88-6*0 Oxirene cation [O(CHCH)]+ (g) 1106.3 1102.6 ± 1.9 kJ/mol 42.0361 ± 0.0016 94664-69-4*0 Ethynol HCCOH (g, gauche triplet) 400.0 397.6 ± 1.9 kJ/mol 42.0367 ± 0.0016 32038-79-2*11 Oxoethylidene HCC(O)H (g, anti-triplet) 265.9 262.6 ± 1.6 kJ/mol 42.0367 ± 0.0016 39920-84-8*11 Hydroperoxymethyl CH2OOH (g) 72.7 65.4 ± 1.4 kJ/mol 47.0333 ± 0.0010 74087-87-9*0 Nitrous acid HONO (g, cis) -71.39 -77.74 ± 0.26 kJ/mol 47.01348 ± 0.00061 7782-77-6*2 Formic acid cation [HC(O)OH]+ (g, anti) 723.7 716.7 ± 1.2 kJ/mol 46.0248 ± 0.0010 50614-05-6*2 Formic acid anion [HC(O)OH]- (g, syn) -256.2 -262.4 ± 1.8 kJ/mol 46.0259 ± 0.0010 19066-82-1*1 Chlorosyl chloride ClClO (g) 134.5 133.2 ± 1.4 kJ/mol 86.9048 ± 0.0018 86825-56-1*0 Trihydrogen dioxide anion [HOHOH]- (g) -487.5 -495.8 ± 1.1 kJ/mol 35.02317 ± 0.00064 12501-19-8*0 Isocyanic acid cation [HNCO]+ (g) 1002.97 1000.31 ± 0.50 kJ/mol 43.02423 ± 0.00086 444010-28-0*0 Fulminic acid cation [HCNO]+ (g) 1215.7 1213.0 ± 1.3 kJ/mol 43.02423 ± 0.00086 114766-65-3*0 Acetic acid CH3C(O)OH (aq, 1500 H2O) -484.91 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*840 Dioxygen O2 (g, singlet) 94.410 94.383 ± 0.000 kJ/mol 31.99880 ± 0.00060 7782-44-7*2 Acetyl chloride CH3C(O)Cl (l) -272.15 ± 0.33 kJ/mol 78.4973 ± 0.0019 75-36-5*500 Methyl formate HC(O)OCH3 (l) -388.50 ± 0.86 kJ/mol 60.0520 ± 0.0017 107-31-3*500 Ethyl formate HC(O)OCH2CH3 (g, anti) -355.5 -374.6 ± 1.4 kJ/mol 74.0785 ± 0.0025 109-94-4*2 2-Methoxy-2-oxoethyl CH2C(O)OCH3 (g, anti) -173.4 -188.5 ± 1.8 kJ/mol 73.0706 ± 0.0025 54668-31-4*2 (Acetyloxy)methyl CH3C(O)OCH2 (g, anti) -174.4 -187.4 ± 1.7 kJ/mol 73.0706 ± 0.0025 2887-49-2*2 NON NON (g) 545.5 542.6 ± 1.7 kJ/mol 44.01288 ± 0.00033 227934-46-5*0 Hydroxyoxoethenyl HOCCO (g) 24.2 22.5 ± 1.8 kJ/mol 57.0281 ± 0.0017 702699-39-6*0 Oxalic acid (C(O)OH)2 (g) -720.9 -731.5 ± 1.3 kJ/mol 90.0349 ± 0.0020 144-62-7*0 Hydrogen difluoride (F)(HF) (g, perp) -187.4 -187.1 ± 1.6 kJ/mol 39.004746 ± 0.000070 12528-21-1*2 Isocyanomethylidyne CNC (g) 672.2 676.5 ± 1.7 kJ/mol 38.0281 ± 0.0016 53590-27-5*0 Cyanomethylidyne CCN (g) 684.7 689.1 ± 2.1 kJ/mol 38.0281 ± 0.0016 4120-02-9*0 Tetrachloromethane CCl4 (l) -108.68 -128.09 ± 0.43 kJ/mol 153.8215 ± 0.0037 56-23-5*500 Dichloromethylene anion [CCl2]- (g) 75.63 77.91 ± 0.77 kJ/mol 82.9166 ± 0.0020 118364-73-1*0 Azanylium [NH2]+ (g) 1266.55 1264.48 ± 0.11 kJ/mol 16.02207 ± 0.00016 15194-15-7*0 Dichloromethylium [CHCl2]+ (g) 894.7 891.5 ± 1.2 kJ/mol 83.9235 ± 0.0020 56932-33-3*0 Dichloromethide [CHCl2]- (g) -40.9 -42.6 ± 2.0 kJ/mol 83.9246 ± 0.0020 32180-91-9*0 Hydrogen fluoride HF (aq, 50 H2O) -321.16 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*822 Chloromethylium [CH2Cl]+ (g) 962.4 958.5 ± 1.2 kJ/mol 49.4787 ± 0.0012 59000-00-9*0 Chloromethylene CHCl (g, triplet) 346.15 346.45 ± 0.89 kJ/mol 48.4713 ± 0.0012 2108-20-5*1 1,2-Dichloroethane CH2ClCH2Cl (cr,l) -165.74 ± 0.56 kJ/mol 98.9586 ± 0.0024 107-06-2*500 1,1-Dichloroethane CH3CHCl2 (cr,l) -163.87 ± 0.48 kJ/mol 98.9586 ± 0.0024 75-34-3*500 Oxochloronium [ClO]+ (g) 1150.86 1150.69 ± 0.66 kJ/mol 51.45155 ± 0.00095 12301-79-0*0 Ethylene cation [CH2CH2]+ (g) 1075.16 1067.95 ± 0.12 kJ/mol 28.0526 ± 0.0016 34470-02-5*0 Pentachloroethane CHCl2CCl3 (g) -151.3 -157.2 ± 1.9 kJ/mol 202.2928 ± 0.0048 76-01-7*0 Triiodide [I3]- (g) -254.3 -257.5 ± 3.4 kJ/mol 380.713959 ± 0.000090 14900-04-0*0 Hydroxydioxonitrate [HON(O)O]- (g) -193.2 -197.6 ± 2.4 kJ/mol 63.01343 ± 0.00091 58875-09-5*0 Chloroform CHCl3 (l) -133.48 ± 0.51 kJ/mol 119.3767 ± 0.0028 67-66-3*590 Chlorodibromomethane CHClBr2 (g) 18.8 -0.0 ± 3.4 kJ/mol 208.2793 ± 0.0023 124-48-1*0 Tribromofluoromethane CBr3F (g) -105.5 -129.5 ± 1.5 kJ/mol 270.7211 ± 0.0031 353-54-8*0 Tribromochloromethane CBr3Cl (g) 77.6 54.8 ± 1.5 kJ/mol 287.1754 ± 0.0032 594-15-0*0 1-Chloro ozone ClOOO (g, cis vdW) 226.3 223.1 ± 2.3 kJ/mol 83.4509 ± 0.0013 141801-66-3*101 Bromochloromethane CH2ClBr (g) -28.2 -42.2 ± 1.3 kJ/mol 129.3833 ± 0.0016 74-97-5*0 Hydrogen fluoride HF (aq, 22 H2O) -321.06 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*902 Ammonia NH3 (aq, undissoc) -80.886 ± 0.053 kJ/mol 17.03056 ± 0.00022 7664-41-7*1000 Fluoromethylene CHF (g) 148.38 148.67 ± 0.43 kJ/mol 32.01704 ± 0.00080 13453-52-6*0 Azidonitrene NNNN (g, Cs) 692.1 687.5 ± 1.4 kJ/mol 56.02696 ± 0.00028 147363-92-6*2 Ethyl iodide CH3CH2I (g) 8.70 -7.18 ± 0.49 kJ/mol 155.9656 ± 0.0016 75-03-6*0 1,2-Dibromoacetylene BrCCBr (g) 333.4 322.5 ± 2.3 kJ/mol 183.8294 ± 0.0026 624-61-3*0 Fluoro(fluorooxy)methylene FCOF (g, vdW triplet) -97.5 -95.6 ± 1.6 kJ/mol 66.00691 ± 0.00085 479587-30-9*101 Chlorite [OClO]- (g) -105.62 -107.79 ± 0.35 kJ/mol 67.4520 ± 0.0011 14998-27-7*0 Fluorooxomethylium [FCO]+ (g) 724.9 724.6 ± 1.2 kJ/mol 47.00795 ± 0.00085 38264-00-5*0 Fluoroisoformyl COF (g) -37.8 -32.4 ± 1.6 kJ/mol 47.00850 ± 0.00085 *1871-24-5*0 Ammonium nitrate (NH4)NO3 (cr,l) -350.29 -365.25 ± 0.18 kJ/mol 80.04344 ± 0.00095 6484-52-2*500 Benzene cation [C6H6]+ (g) 992.49 976.03 ± 0.23 kJ/mol 78.1113 ± 0.0048 34504-50-2*0 Trifluoromethide [CF3]- (g) -637.6 -639.4 ± 1.8 kJ/mol 69.00646 ± 0.00080 54128-17-5*0 Diiodide [I2]- (g) -178.13 -180.72 ± 0.48 kJ/mol 253.809489 ± 0.000060 12190-71-5*0 Nitronium [ONO]+ (g) 961.78 958.23 ± 0.20 kJ/mol 46.00499 ± 0.00060 14522-82-8*0 m-Chlorophenide [C6H4Cl]- (g) 172.2 162.0 ± 1.6 kJ/mol 111.5492 ± 0.0049 77748-34-6*0 p-Chlorophenide [C6H4Cl]- (g) 179.2 168.7 ± 1.5 kJ/mol 111.5492 ± 0.0049 77748-42-6*0 o-Chlorophenide [C6H4Cl]- (g) 158.2 148.3 ± 1.6 kJ/mol 111.5492 ± 0.0049 72863-53-7*0 Vinylidene CCH2 (g, triplet) 610.39 610.10 ± 0.50 kJ/mol 26.0373 ± 0.0016 2143-69-3*1 2-Oxopropylium [CH3C(O)CH2]+ (g) 784.4 770.6 ± 1.8 kJ/mol 57.0707 ± 0.0024 54088-52-7*0 Bromo hypobromite BrOBr (g) 120.5 104.0 ± 1.2 kJ/mol 175.8074 ± 0.0020 21308-80-5*0 2,3-Butanedione CH3C(O)C(O)CH3 (g) -310.85 -327.42 ± 0.66 kJ/mol 86.0892 ± 0.0033 431-03-8*0 1,2-Dibromoethane CH2BrCH2Br (g) -11.6 -38.5 ± 1.2 kJ/mol 187.8612 ± 0.0026 106-93-4*0 Peroxyimidogen NOO (g) 405.4 403.4 ± 1.9 kJ/mol 46.00554 ± 0.00060 *60488-31-5*0 2-Propynal CHCCHO (g) 135.5 133.4 ± 1.4 kJ/mol 54.0474 ± 0.0024 624-67-9*0 Fluorosyl fluoride FFO (g, triplet) 192.6 193.1 ± 2.3 kJ/mol 53.99621 ± 0.00030 86825-57-2*1 1-Isocyanoethylidene CH3CNC (g, triplet) 545.4 540.6 ± 1.6 kJ/mol 53.0627 ± 0.0024 *498544-34-6*1 3-Imino-2-propen-1-ylidene CHCHCNH (g, anti-triplet) 571.8 566.8 ± 1.6 kJ/mol 53.0627 ± 0.0024 916765-05-4*21 2-(Methylidyneamino)ethenyl CHCHNCH (g, anti-triplet) 634.4 629.7 ± 1.6 kJ/mol 53.0627 ± 0.0024 123416-74-0*21 Azete (CHCHCH)N (g) 469.4 461.3 ± 1.5 kJ/mol 53.0627 ± 0.0024 287-24-1*0 Oxadiazirene O(NN) (g) 351.7 349.9 ± 1.7 kJ/mol 44.01288 ± 0.00033 227934-45-4*0 2-Cyanovinylium [CHCHCN]+ (g, anti triplet) 1517.2 1515.1 ± 1.8 kJ/mol 52.0542 ± 0.0024 85398-67-0*21 2-Cyanovinyl anion [CHCHCN]- (g, syn) 263.7 260.8 ± 1.8 kJ/mol 52.0553 ± 0.0024 *85398-67-0*2 2-Isocyanovinyl CHCHNC (g, anti) 543.1 541.2 ± 1.7 kJ/mol 52.0547 ± 0.0024 225798-14-1*1 3-Oxo-1,2-propadienylidene CCCO (g) 330.0 335.9 ± 2.0 kJ/mol 52.0315 ± 0.0024 11127-17-6*0 Fulvene CH2C(CHCHCHCH) (g) 231.4 215.3 ± 1.4 kJ/mol 78.1118 ± 0.0048 497-20-1*0 5-Methyl-1,3-cyclopentadiene CH3CH(CHCHCHCH) (g) 133.4 110.4 ± 1.5 kJ/mol 80.1277 ± 0.0048 96-38-8*0 Carbonic acid C(O)(OH)2 (g) -602.78 -612.09 ± 0.75 kJ/mol 62.0248 ± 0.0012 463-79-6*0 Peroxyformic acid HC(O)OOH (g, gauche) -265.3 -273.2 ± 1.5 kJ/mol 62.0248 ± 0.0012 107-32-4*3 Ethynylene cation [C2]+ (g) 1965.20 1971.79 ± 0.50 kJ/mol 24.0209 ± 0.0016 12595-79-8*0 Chlorine difluoride ClFF (g) 22.5 23.9 ± 1.9 kJ/mol 73.44951 ± 0.00090 91483-78-2*0 Dihydrogen cation [H2]+ (g) 1488.364 1488.480 ± 0.000 kJ/mol 2.01533 ± 0.00014 12184-90-6*0 Hydroxylamine cation [NH2OH]+ (g) 857.7 847.9 ± 1.6 kJ/mol 33.02941 ± 0.00037 62675-55-2*0 Perchloryloxy OCl(O)(O)O (g) 248.6 241.0 ± 1.8 kJ/mol 99.4503 ± 0.0015 12133-63-0*0 Hydrogen fluoride HF (l) -302.40 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*590 Cyclopropylidene C(CH2CH2) (g, triplet) 544.7 535.8 ± 1.5 kJ/mol 40.0639 ± 0.0024 2143-70-6*2 Trioxidaniumyl [HOOOH]+ (g, c, t) 935.2 926.1 ± 1.5 kJ/mol 50.01353 ± 0.00091 161321-37-5*3 Propynylidene cation [HCCCH]+ (g) 1410.8 1413.4 ± 1.3 kJ/mol 38.0474 ± 0.0024 75123-91-0*0 Propynylidene HCCCH (g, trans singlet) 597.3 599.1 ± 1.1 kJ/mol 38.0480 ± 0.0024 67152-18-5*4 Perchlorate [OCl(O)(O)O]- (g) -263.2 -272.1 ± 2.2 kJ/mol 99.4508 ± 0.0015 14797-73-0*0 Propadienylidenide [CH2CC]- (g) 381.11 382.01 ± 0.41 kJ/mol 38.0485 ± 0.0024 109292-49-1*0 1,2-Propadien-1-ylium-1-yl [CH2CC]+ (g) 1561.6 1562.8 ± 1.4 kJ/mol 38.0474 ± 0.0024 110714-00-6*0 Deuterium atom cation D+ (g) 1532.210 1534.123 ± 0.000 kJ/mol 2.01355319809 ± 0.00000000040 14464-47-2*0 Nitrogen hydride oxide NH3O (g) 71.2 60.0 ± 1.5 kJ/mol 33.02996 ± 0.00037 38544-48-8*0 Hydrogen fluoride HF (aq, 10 H2O) -320.88 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*815 Iminomethyl anion [HCNH]- (g, cis) 252.6 248.9 ± 1.8 kJ/mol 28.03387 ± 0.00082 90623-30-6*2 n-Pentane CH3CH2CH2CH2CH3 (cr,l) -156.05 -173.02 ± 0.31 kJ/mol 72.1488 ± 0.0041 109-66-0*500 iso-Pentane CH3CH2CH(CH3)2 (l) -178.43 ± 0.43 kJ/mol 72.1488 ± 0.0041 78-78-4*500 neo-Pentane C(CH3)4 (l) -189.90 ± 0.40 kJ/mol 72.1488 ± 0.0041 463-82-1*500 Cyclopentane CH2(CH2CH2CH2CH2) (l) -105.12 ± 0.39 kJ/mol 70.1329 ± 0.0041 287-92-3*590 Aminooxy cation [NH2O]+ (g) 946.09 938.96 ± 0.79 kJ/mol 32.02147 ± 0.00034 *51375-41-8*0 Fluorosyl fluoride anion [FFO]- (g, doublet) -147.2 -146.9 ± 3.0 kJ/mol 53.99675 ± 0.00030 *86825-57-2*2 1,5-Hexadiene CH2CHCH2CH2CHCH2 (g) 108.38 83.79 ± 0.40 kJ/mol 82.1436 ± 0.0049 592-42-7*0 1,3-Butadiyne-1,4-diyl CCCC (g) 1052.47 1062.45 ± 0.68 kJ/mol 48.0428 ± 0.0032 78015-07-3*0 Trioxidanylium [HOOO]+ (g, cis) 1085.2 1078.9 ± 1.4 kJ/mol 49.00559 ± 0.00090 74241-49-9*2 Ethoxy CH3CH2O (g) 1.27 -12.16 ± 0.47 kJ/mol 45.0605 ± 0.0017 2154-50-9*0 Dihydrogen fluoride anion [(HF)(H)]- (g, singlet) -61.9 -60.5 ± 3.2 kJ/mol 21.01483 ± 0.00014 117339-92-1*2 Hydrogen cyanide cation [HCN]+ (g) 1442.52 1442.05 ± 0.20 kJ/mol 27.02483 ± 0.00081 12601-62-6*0 Dihydrooxooxygen cation [(H2O)O]+ (g) 994.8 988.1 ± 1.6 kJ/mol 34.01413 ± 0.00062 177329-59-8*0 1-Hydrazinylium-1-yl [NNH2]+ (g) 1143.4 1136.4 ± 1.4 kJ/mol 30.02881 ± 0.00020 63986-30-1*0 Chlorine oxide peroxide OClOO (g, vdW) 226.5 227.4 ± 2.5 kJ/mol 83.4509 ± 0.0013 141801-67-4*100 Hydroxyaminylium [HNOH]+ (g, cis) 1048.5 1041.4 ± 2.6 kJ/mol 32.02147 ± 0.00034 66097-71-0*2 Trioxodinitrate anion [ONN(O)O]- (g, vdW) -104.3 -107.5 ± 1.9 kJ/mol 76.01223 ± 0.00091 194856-62-7*100 (E)-Diazene anion [HNNH]- (g, trans) 265.5 258.7 ± 2.0 kJ/mol 30.02991 ± 0.00020 *59952-06-6*0 Hydroxyamidogen anion [HNOH]- (g) 90.7 84.8 ± 2.8 kJ/mol 32.02257 ± 0.00034 *66097-71-0*0 Dicarbon monoxide cation [CCO]+ (g) 1433.9 1439.0 ± 2.1 kJ/mol 40.0203 ± 0.0016 12287-08-0*0 Nitrilomethylium [CN]+ (g) 1783.15 1786.63 ± 0.49 kJ/mol 26.01689 ± 0.00080 12539-57-0*0 C=O-C cation [COC]+ (g, quartet) 1816.8 1820.9 ± 2.0 kJ/mol 40.0203 ± 0.0016 83483-98-1*2 Oxirene anion [O(CHCH)]- (g) 288.2 285.3 ± 2.2 kJ/mol 42.0372 ± 0.0016 *157-18-6*0 (Z)-Diazene cation [HNNH]+ (g, cis) 1157.0 1150.1 ± 1.3 kJ/mol 30.02881 ± 0.00020 86631-37-0*0 Oxoethylidene HCC(O)H (g, triplet) 261.1 258.2 ± 1.1 kJ/mol 42.0367 ± 0.0016 39920-84-8*1 Formic acid anion [HC(O)OH]- (g, anti) -241.2 -247.0 ± 1.9 kJ/mol 46.0259 ± 0.0010 19066-82-1*2 Nitrosyl nitrate ON(O2)NO (g, perp) 70.6 62.3 ± 1.8 kJ/mol 92.0111 ± 0.0012 *15969-55-8*0 Dioxirane cation [CH2(OO)]+ (g) 1050.8 1043.1 ± 2.0 kJ/mol 46.0248 ± 0.0010 232262-10-1*0 Dioxymethyl cation [CH2OO]+ (g) 1074.9 1068.5 ± 1.8 kJ/mol 46.0248 ± 0.0010 232262-11-2*0 Oxadiazirine anion [O(NN)]- (g) 95.1 95.5 ± 2.9 kJ/mol 44.01343 ± 0.00033 350586-31-1*0 Dioxymethylene HCOO (g, cis) 341.8 339.8 ± 3.0 kJ/mol 45.0174 ± 0.0010 438586-67-5*2 OH-CO vdW complex (OH)(CO) (g, vdW) -80.26 -76.54 ± 0.88 kJ/mol 45.0174 ± 0.0010 *2564-85-4*100 CO-HO vdW complex (CO)(HO) (g, vdW) -77.4 -73.2 ± 1.3 kJ/mol 45.0174 ± 0.0010 *2564-84-3*100 Nitrous acid HONO (g) -73.005 -78.661 ± 0.079 kJ/mol 47.01348 ± 0.00061 7782-77-6*0 Cyanato cation [NCO]+ (g) 1261.47 1261.98 ± 0.58 kJ/mol 42.01629 ± 0.00086 17247-99-3*0 Ethane cation [CH3CH3]+ (g) 1043.14 1029.13 ± 0.59 kJ/mol 30.0685 ± 0.0017 34488-65-8*0 Nitrosomethyliumylidene [CNO]+ (g) 1509.6 1510.7 ± 1.7 kJ/mol 42.01629 ± 0.00086 67197-19-7*0 Fulminate [CNO]- (g) 59.4 59.7 ± 1.8 kJ/mol 42.01739 ± 0.00086 28269-67-2*0 Acetic acid CH3C(O)OH (l) -484.10 -483.67 ± 0.18 kJ/mol 60.0520 ± 0.0017 64-19-7*500 Acetic acid CH3C(O)OH (aq, 75 H2O) -484.71 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*825 Acetic acid CH3C(O)OH (aq, 700 H2O) -484.90 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*835 Diazenide [NNH]- (g, triplet) 347.4 344.6 ± 1.6 kJ/mol 29.02197 ± 0.00016 71004-29-0*1 Hydrogen bromide HBr (aq, 600 H2O) -120.16 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*834 Glyoxal OCHCHO (g, cis) -189.30 -194.75 ± 0.75 kJ/mol 58.0361 ± 0.0017 107-22-2*2 Glyoxal OCHCHO (g) -207.75 -213.31 ± 0.61 kJ/mol 58.0361 ± 0.0017 107-22-2*0 Ethynediol HOCCOH (g) -18.4 -22.2 ± 1.7 kJ/mol 58.0361 ± 0.0017 16005-17-7*0 Hydrogen bromide HBr (aq, 5000 H2O) -120.46 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*844 Dimethylaminylium [(CH3)2N]+ (g) 1040.2 1024.7 ± 1.8 kJ/mol 44.0752 ± 0.0017 49784-85-2*0 Diisocyanogen CNNC (g) 610.3 612.6 ± 1.8 kJ/mol 52.0349 ± 0.0016 78800-21-2*0 Dichloromethylene CCl2 (g, triplet) 313.63 314.84 ± 0.90 kJ/mol 82.9161 ± 0.0020 1605-72-7*1 Xenon cation Xe+ (g) 1170.354 1170.354 ± 0.0062 kJ/mol 131.2895 ± 0.0200 24203-25-6*0 Chloromethyliumyl [CHCl]+ (g) 1207.4 1207.6 ± 2.0 kJ/mol 48.4708 ± 0.0012 89877-51-0*0 Chloromethylene anion [CHCl]- (g) 203.44 204.26 ± 0.94 kJ/mol 48.4719 ± 0.0012 75466-08-9*0 Chlorohydroxymethyl CH(Cl)OH (g, anti-gauche) -46.1 -51.7 ± 2.0 kJ/mol 65.4787 ± 0.0012 147139-06-8*2 Hydrogen fluoride HF (aq, 60 H2O) -321.18 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*823 Aminyliumyl [NH]+ (g) 1659.03 1659.95 ± 0.24 kJ/mol 15.014131 ± 0.000099 19067-62-0*0 1,1,2-Trichloroethane CH2ClCHCl2 (l) -188.6 ± 1.4 kJ/mol 133.4033 ± 0.0031 79-00-5*500 Ethylene anion [CH2CH2]- (g, anti ?) 232.0 224.4 ± 2.0 kJ/mol 28.0537 ± 0.0016 34527-91-8*1 1,1,1,2-Tetrachloroethane CH2ClCCl3 (cr,l) -193.5 ± 1.1 kJ/mol 167.8481 ± 0.0039 630-20-6*500 Fluorodioxidenium [FOO]+ (g) 1221.9 1219.5 ± 2.0 kJ/mol 50.99665 ± 0.00060 139584-95-5*0 Hexachloroethane CCl3CCl3 (cr,l) -216.5 ± 2.8 kJ/mol 236.7376 ± 0.0056 67-72-1*500 3-Chloro-3-methyl-3H-diazirine (NN)CClCH3 (g) 251.4 239.5 ± 2.7 kJ/mol 90.5114 ± 0.0019 4222-21-3*0 trans-1,2-Dichloroethene CHClCHCl (g, trans) 5.30 -0.12 ± 0.54 kJ/mol 96.9427 ± 0.0024 156-60-5*0 Fluorodioxidanide [FOO]- (g) -256.8 -256.1 ± 1.9 kJ/mol 50.99775 ± 0.00060 23553-17-5*0 Dioxofluorine OFO (g) 524.0 523.2 ± 1.0 kJ/mol 50.99720 ± 0.00060 175861-93-5*0 Fluorochlorobromomethane CHFClBr (g) -218.2 -230.9 ± 4.9 kJ/mol 147.3737 ± 0.0016 593-98-6*0 Methyleneoxonium cation [CH2OH2]+ (g) 827.7 818.2 ± 1.7 kJ/mol 32.04131 ± 0.00090 *177788-17-9*0 Fluoromethyliumyl [CHF]+ (g) 1116.6 1116.9 ± 1.7 kJ/mol 32.01649 ± 0.00080 89877-52-1*0 Fluoromethylene anion [CHF]- (g) 95.93 96.46 ± 0.61 kJ/mol 32.01759 ± 0.00080 71267-42-0*0 Azidonitrene NNNN (g, C2h) 660.8 657.6 ± 1.6 kJ/mol 56.02696 ± 0.00028 147363-92-6*1 Polytetrafluoroethylene CF2CF2 (s) -829.63 ± 0.58 kJ/mol 100.0150 ± 0.0016 9002-84-0*591 Tetraoxidanyl (HO2)(O2) (g, vdW) 2.0 0.2 ± 3.0 kJ/mol 65.0055 ± 0.0012 69696-93-1*100 Hydroxymethanide [CH2OH]- (g) 9.4 2.8 ± 1.7 kJ/mol 31.03447 ± 0.00088 55830-71-2*0 Trifluoride ion [F3]- (g) -348.8 -349.7 ± 2.6 kJ/mol 56.9957582 ± 0.0000015 25730-99-8*0 Hydrogen chloride HCl (aq, 2000 H2O) -166.683 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*841 Nitric acid HON(O)O (aq, 1000 H2O) -206.32 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*839 trans-1,2-Difluoroethene CHFCHF (g, trans) -299.66 -306.10 ± 0.90 kJ/mol 64.0341 ± 0.0016 1630-78-0*0 Fluoroethynide [CCF]- (g) 133.3 137.5 ± 1.5 kJ/mol 43.0204 ± 0.0016 85905-56-2*0 Formyl fluoride cation [CHFO]+ (g) 816.6 813.3 ± 1.3 kJ/mol 48.01589 ± 0.00086 99766-68-4*0 Formaldehyde CH2O (g, singlet) -105.378 -109.217 ± 0.097 kJ/mol 30.02598 ± 0.00087 50-00-0*2 Formyl fluoride [FCO]- (g) -405.1 -403.7 ± 1.6 kJ/mol 47.00905 ± 0.00085 62227-71-8*0 Fluoroisoformyl cation [COF]+ (g) 1347.4 1349.5 ± 1.9 kJ/mol 47.00795 ± 0.00085 *1871-25-6*0 Nitric acid HON(O)O (cr,l) -179.01 -173.29 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*500 Hydrogen peroxide cation [H2O2]+ (g, cis) 930.98 924.12 ± 0.98 kJ/mol 34.01413 ± 0.00062 12325-10-9*2 Fluoroniumyl ion [HF]+ (g) 1275.565 1275.796 ± 0.050 kJ/mol 20.005795 ± 0.000070 12381-92-9*0 1-Chloro ozone anion [ClOOO]- (g, perp) -108.9 -111.4 ± 2.2 kJ/mol 83.4514 ± 0.0013 224299-15-4*3 o-Benzyne cation [C6H4]+ (g) 1392.7 1384.7 ± 1.7 kJ/mol 76.0954 ± 0.0048 70220-84-7*0 Hydrofluorate ion [HF]- (g) -75.6 -75.1 ± 1.8 kJ/mol 20.006892 ± 0.000070 37249-79-9*0 m-Benzyne cation [C6H4]+ (g) 1364.7 1356.1 ± 1.8 kJ/mol 76.0954 ± 0.0048 121058-08-0*0 p-Benzyne C6H4 (g, triplet) 603.4 594.1 ± 1.2 kJ/mol 76.0960 ± 0.0048 3355-34-8*1 Benzylium [C6H5CH2]+ (g) 929.38 909.89 ± 0.60 kJ/mol 91.1299 ± 0.0056 6711-19-9*0 Bifluoride [FHF]- (g) -705.20 -709.05 ± 0.36 kJ/mol 39.005295 ± 0.000070 18130-74-0*0 1,3-Cycloheptadiene CH2(CHCHCHCHCH2CH2) (g, c-c) 123.29 94.18 ± 0.78 kJ/mol 94.1543 ± 0.0056 4054-38-0*1 Tropylium [CH(CHCHCHCHCHCH)]+ (g) 898.0 878.2 ± 1.1 kJ/mol 91.1299 ± 0.0056 26811-28-9*0 Dioxaziridinyl cation [N(OO)]+ (g) 1365.9 1363.3 ± 1.7 kJ/mol 46.00499 ± 0.00060 *66252-29-7*0 Acetylene anion [HCCH]- (g, trans ?) 356.8 356.7 ± 1.9 kJ/mol 26.0378 ± 0.0016 50443-89-5*1 Hydroxymethylene cation [HCOH]+ (g, cis) 986.3 982.7 ± 1.6 kJ/mol 30.02543 ± 0.00087 135395-06-1*2 Hydroxymethylene cation [HCOH]+ (g, gauche quartet) 1482.1 1479.4 ± 1.9 kJ/mol 30.02543 ± 0.00087 135395-06-1*3 Acetone enol CH3C(OH)CH2 (g, anti) -147.4 -164.6 ± 1.3 kJ/mol 58.0791 ± 0.0025 29456-04-0*2 Hydroxymethylene anion [HCOH]- (g, cis) 160.2 157.5 ± 1.7 kJ/mol 30.02653 ± 0.00087 207914-87-2*2 Dioxaziridinyl anion [N(OO)]- (g) 295.9 293.4 ± 1.7 kJ/mol 46.00609 ± 0.00060 66252-31-1*0 cis-1,2-Dibromoethene CHBrCHBr (g, cis) 121.1 100.5 ± 2.1 kJ/mol 185.8453 ± 0.0026 590-11-4*0 Hydroxymethylene anion [HCOH]- (g, gauche quartet) 334.0 334.8 ± 2.1 kJ/mol 30.02653 ± 0.00087 207914-87-2*3 1,1-Dibromoethane CH3CHBr2 (g) -5.1 -32.1 ± 1.8 kJ/mol 187.8612 ± 0.0026 557-91-5*0 Krypton hydride cation [KrH]+ (g) 1106.33 1104.54 ± 0.69 kJ/mol 84.8074 ± 0.1000 37276-90-7*0 Hydrogen chloride HCl (aq, 75 H2O) -165.557 ± 0.026 kJ/mol 36.46064 ± 0.00090 7647-01-0*825 Aquacarbon H2OC (g, singlet vdW) 467.6 465.5 ± 1.9 kJ/mol 30.02598 ± 0.00087 81434-73-3*102 Formaldoxime CH2NOH (g, cis) 50.8 40.0 ± 1.8 kJ/mol 45.04066 ± 0.00088 75-17-2*2 Peroxyimidogen cation [NOO]+ (g) 1409.6 1406.8 ± 1.9 kJ/mol 46.00499 ± 0.00060 *60488-32-6*0 Oxaziridine CH2(NHO) (g) 115.8 104.0 ± 2.1 kJ/mol 45.04066 ± 0.00088 6827-26-5*0 Cyanoethynyl CCCN (g) 715.6 722.0 ± 1.2 kJ/mol 50.0388 ± 0.0024 62435-43-2*0 Hydrogen fluoride HF (aq, 18 H2O) -321.03 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*901 Trioxidanyl HOOO (g, cis) 26.30 23.02 ± 0.19 kJ/mol 49.00614 ± 0.00090 12500-78-6*2 Peroxyimidogen anion [NOO]- (g) 165.0 162.6 ± 1.7 kJ/mol 46.00609 ± 0.00060 60488-31-5*0 Aquacarbon cation [H2OC]+ (g) 1196.1 1193.0 ± 1.7 kJ/mol 30.02543 ± 0.00087 *81434-73-3*0 Nirous oxide cation [NNO]+ (g) 1329.67 1326.78 ± 0.12 kJ/mol 44.01233 ± 0.00033 12269-46-4*0 2-Methylene-2H-azirine (CHN)CCH2 (g) 404.2 396.8 ± 1.7 kJ/mol 53.0627 ± 0.0024 110027-86-6*0 Hydroxylamine NH2OH (g, cis) -15.4 -25.9 ± 1.4 kJ/mol 33.02996 ± 0.00037 7803-49-8*2 2-Cyanovinylium [CHCHCN]+ (g, syn triplet) 1517.4 1515.2 ± 1.8 kJ/mol 52.0542 ± 0.0024 85398-67-0*22 2-Cyanovinyl anion [CHCHCN]- (g, anti) 266.1 263.2 ± 1.8 kJ/mol 52.0553 ± 0.0024 *85398-67-0*1 2-Isocyanovinyl CHCHNC (g, syn) 544.6 542.6 ± 1.7 kJ/mol 52.0547 ± 0.0024 225798-14-1*2 Cyanomethylene HCCN (g, singlet) 529.5 530.6 ± 1.3 kJ/mol 39.0361 ± 0.0016 2612-62-6*2 Isocyanomethylene HCNC (g, triplet) 586.3 587.3 ± 1.7 kJ/mol 39.0361 ± 0.0016 78694-65-2*2 Cyclobutenyl CH2(CHCHCH) (g) 335.3 322.8 ± 2.2 kJ/mol 53.0825 ± 0.0032 24669-29-2*0 Butyraldehyde CH3CH2CH2CHO (g) -185.46 -205.83 ± 0.85 kJ/mol 72.1057 ± 0.0033 123-72-8*0 Nitrosyl fluoride FNO (g) -85.81 -88.18 ± 0.93 kJ/mol 49.00454 ± 0.00031 7789-25-5*0 Chloroallene CH2CCHCl (g) 181.5 174.9 ± 1.6 kJ/mol 74.5086 ± 0.0026 3223-70-9*0 1-Chloropropyne CH3CCCl (g) 191.3 187.2 ± 1.6 kJ/mol 74.5086 ± 0.0026 7747-84-4*0 Chlorine difluoride anion [FClF]- (g) -504.9 -505.7 ± 1.9 kJ/mol 73.45005 ± 0.00090 16892-05-0*0 Methylcyclopentane CH3CH(CH2CH2CH2CH2) (g) -69.36 -106.32 ± 0.38 kJ/mol 84.1595 ± 0.0049 96-37-7*0 Dihydrogen fluoride (H)(HF) (g) -55.9 -54.9 ± 1.6 kJ/mol 21.01428 ± 0.00014 12592-22-2*1 1-Chloro ozone anion [ClOOO]- (g, cis) -66.8 -68.7 ± 2.1 kJ/mol 83.4514 ± 0.0013 224299-15-4*1 Quartz SiO2 (cr, quartz) -906.11 -911.09 ± 0.94 kJ/mol 60.08430 ± 0.00067 14808-60-7*505 n-Hexane CH3CH2CH2CH2CH2CH3 (cr,l) -179.97 -198.63 ± 0.34 kJ/mol 86.1754 ± 0.0049 110-54-3*500 Cyclohexane CH2(CH2CH2CH2CH2CH2) (l) -156.14 ± 0.33 kJ/mol 84.1595 ± 0.0049 110-82-7*500 Aminooxy anion [NH2O]- (g) 47.4 40.5 ± 1.7 kJ/mol 32.02257 ± 0.00034 51375-41-8*0 iso-Proplylide [CH3CHCH3]- (g) 128.5 110.1 ± 1.6 kJ/mol 43.0882 ± 0.0024 25012-80-0*0 Aminomethyliumylidene [CNH2]+ (g) 1168.3 1165.1 ± 2.2 kJ/mol 28.03277 ± 0.00082 86784-42-1*0 1-Hydroxyethanide [CH3CHOH]- (g) -20.3 -33.7 ± 2.2 kJ/mol 45.0610 ± 0.0017 88032-18-2*0 Nitrosyl nitrate ONONO2 (g, trans) 48.3 40.3 ± 1.8 kJ/mol 92.0111 ± 0.0012 15969-55-8*1 Acetaldehyde anion [CH3CHO]- (g) -62.2 -72.5 ± 2.2 kJ/mol 44.0531 ± 0.0017 60427-04-5*0 1-Hydroxyethenyl CH2COH (g) 121.31 114.93 ± 0.99 kJ/mol 43.0446 ± 0.0016 81847-74-7*0 Ozone cation [OOO]+ (g) 1352.871 1350.531 ± 0.041 kJ/mol 47.99765 ± 0.00090 12596-82-6*0 Deuterium hydride cation [HD]+ (g) 1490.498 1490.587 ± 0.000 kJ/mol 3.021493 ± 0.000070 12181-16-7*0 Ketene cation [CH2CO]+ (g) 882.22 879.05 ± 0.12 kJ/mol 42.0361 ± 0.0016 64999-16-2*0 Ketene anion [CH2CO]- (g) -16.0 -19.1 ± 2.2 kJ/mol 42.0372 ± 0.0016 56391-79-8*0 Methylaminilium [CH3NH]+ (g) 1134.9 1125.1 ± 2.1 kJ/mol 30.04865 ± 0.00085 49784-84-1*0 Oxoethenylium [HCCO]+ (g) 1139.7 1142.4 ± 2.1 kJ/mol 41.0282 ± 0.0016 92056-63-8*0 Trioxidanylium [HOOO]+ (g) 1070.4 1064.2 ± 1.4 kJ/mol 49.00559 ± 0.00090 74241-49-9*0 Chloroniumyl ion [HCl]+ (g) 1137.797 1137.731 ± 0.0051 kJ/mol 36.46009 ± 0.00090 12258-94-5*0 Oxiranylidene CH2(CO) (g, triplet) 456.1 452.1 ± 2.2 kJ/mol 42.0367 ± 0.0016 50983-85-2*1 Oxiranylidene cation [CH2(CO)]+ (g) 1165.4 1161.9 ± 2.5 kJ/mol 42.0361 ± 0.0016 *50983-85-2*0 Oxiranylidene anion [CH2(CO)]- (g) 236.4 232.4 ± 2.3 kJ/mol 42.0372 ± 0.0016 *50983-86-3*0 Hydrooxonitrate [HNO]- (g) 78.59 75.68 ± 0.99 kJ/mol 31.01463 ± 0.00032 66057-02-1*0 Methyl hydroperoxide cation [CH3OOH]+ (g) 833.4 819.3 ± 2.2 kJ/mol 48.0407 ± 0.0010 112465-88-0*0 Dibromine Br2 (aq) -2.16 ± 0.20 kJ/mol 159.8080 ± 0.0020 7726-95-6*800 Methoxyoxoniumylidene [CH3OO]+ (g) 1013.65 1004.82 ± 0.69 kJ/mol 47.0328 ± 0.0010 86475-50-5*0 Hydroxyimidogen anion [NOH]- (g) 229.8 227.4 ± 2.2 kJ/mol 31.01463 ± 0.00032 *35337-59-8*0 Dioxirane anion [CH2(OO)]- (g) -173.0 -179.8 ± 3.4 kJ/mol 46.0259 ± 0.0010 *157-26-6*0 Dioxymethyl anion [CH2OO]- (g) 54.9 49.8 ± 1.4 kJ/mol 46.0259 ± 0.0010 93207-29-5*0 Hydrogen chloride HCl (aq, 1500 H2O) -166.637 ± 0.025 kJ/mol 36.46064 ± 0.00090 7647-01-0*840 Hydrogen bromide HBr (aq, 2570 H2O) -120.39 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*952 Cyclopropylide [CH(CH2CH2)]- (g) 264.7 251.9 ± 1.8 kJ/mol 41.0723 ± 0.0024 1724-45-4*0 H-CO2 vdW complex (H)(OCO) (g, vdW) -178.3 -177.5 ± 2.1 kJ/mol 45.0174 ± 0.0010 *2564-83-2*100 Chlorosyl chloride cation [ClClO]+ (g) 1132.6 1130.8 ± 2.0 kJ/mol 86.9043 ± 0.0018 *86825-56-1*0 Hydrogen bromide HBr (aq, 3000 H2O) -120.41 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*842 2-Propanol CH3CH(OH)CH3 (cr,l) -306.15 -318.96 ± 0.36 kJ/mol 60.0950 ± 0.0025 67-63-0*500 1-Propanol CH3CH2CH2OH (cr,l) -290.53 -302.71 ± 0.24 kJ/mol 60.0950 ± 0.0025 71-23-8*500 Hydroxyoxoammoniumyl [HONO]+ (g) 984.1 977.7 ± 1.8 kJ/mol 47.01293 ± 0.00061 80371-48-8*0 Isocyanomethylium [CH2NC]+ (g) 1272.8 1270.6 ± 2.2 kJ/mol 40.0435 ± 0.0016 78269-43-9*0 Dinitrogen pentoxide O2NONO2 (cr,l) -41.04 ± 0.42 kJ/mol 108.0105 ± 0.0015 10102-03-1*500 1,2-Propadien-1-yl-3-ylidene anion [CCC]- (g) 622.0 629.4 ± 1.3 kJ/mol 36.0326 ± 0.0024 109292-47-9*0 Oxazirinyl cation [C(NO)]+ (g) 1565.4 1566.1 ± 2.3 kJ/mol 42.01629 ± 0.00086 *228850-18-8*0 Oxazirinyl anion [C(NO)]- (g) 448.1 448.9 ± 2.4 kJ/mol 42.01739 ± 0.00086 28269-68-3*0 Chlorosyl chloride anion [ClClO]- (g) -185.4 -184.7 ± 2.3 kJ/mol 86.9053 ± 0.0018 *86825-55-0*0 1-Propenylidene CH3CHC (g, triplet) 630.3 622.8 ± 1.7 kJ/mol 40.0639 ± 0.0024 70277-78-0*2 2-Chloro ozone anion [ClO(O)O]- (g) -103.4 -105.6 ± 3.2 kJ/mol 83.4514 ± 0.0013 *141801-67-4*0 Hydrogen bromide HBr (aq, 2000 H2O) -120.36 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*841 1-Methoxyethenol CH2C(OH)OCH3 (g, anti-syn) -284.9 -304.2 ± 1.7 kJ/mol 74.0785 ± 0.0025 4453-91-2*1 Hydrogen chloride HCl (aq, 74 H2O) -165.546 ± 0.027 kJ/mol 36.46064 ± 0.00090 7647-01-0*953 Chloryl chloride ClCl(O)O (g) 126.1 122.1 ± 1.7 kJ/mol 102.9042 ± 0.0019 117489-73-3*0 Trifluorine cation [F3]+ (g) 1529.5 1527.4 ± 2.3 kJ/mol 56.9946610 ± 0.0000015 64710-22-1*0 Ethanium [C2H7]+ (g, classical Cs I) 888.7 870.3 ± 1.8 kJ/mol 31.0764 ± 0.0017 24669-33-8*2 Ethyl formate HC(O)OCH2CH3 (cr,l) -426.0 ± 1.2 kJ/mol 74.0785 ± 0.0025 109-94-4*500 Ethanium [C2H7]+ (g, classical Cs II) 895.1 877.3 ± 1.9 kJ/mol 31.0764 ± 0.0017 24669-33-8*3 Propionic acid CH3CH2C(O)OH (g, anti) -415.8 -433.4 ± 1.4 kJ/mol 74.0785 ± 0.0025 79-09-4*2 Methylimidogen anion [CH3N]- (g) 321.1 313.5 ± 1.4 kJ/mol 29.04181 ± 0.00083 82539-34-2*0 Cyanogen cation [NCCN]+ (g) 1598.23 1600.45 ± 0.43 kJ/mol 52.0343 ± 0.0016 37354-81-7*0 Isocyanogen CNCN (g) 411.0 413.3 ± 1.6 kJ/mol 52.0349 ± 0.0016 83951-85-3*0 Hydrogen difluoride cation [FFH]+ (g, singlet) 1174.3 1171.3 ± 1.5 kJ/mol 39.004198 ± 0.000070 *126950-54-7*2 Diazoethenylidene NNCC (g) 658.7 661.3 ± 1.8 kJ/mol 52.0349 ± 0.0016 130760-10-0*0 Isocyanomethyliumylidene [CNC]+ (g) 1615.7 1621.2 ± 1.9 kJ/mol 38.0276 ± 0.0016 78271-45-1*0 Isocyanomethylidyne anion [CNC]- (g) 479.2 482.9 ± 2.0 kJ/mol 38.0287 ± 0.0016 *53590-27-5*0 Cyanomethyliumylidene [CCN]+ (g) 1719.8 1725.3 ± 2.1 kJ/mol 38.0276 ± 0.0016 76619-90-4*0 Cyanomethylidyne anion [CCN]- (g) 410.0 413.7 ± 2.2 kJ/mol 38.0287 ± 0.0016 12373-35-2*0 2,3-didehydro-1H-azirin-1-yl N(CC) (g) 720.3 724.4 ± 2.1 kJ/mol 38.0281 ± 0.0016 439586-06-8*0 Hydrogen fluoride HF (aq, 55 H2O) -321.17 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*905 Tribromine Br3 (g) 155.9 134.2 ± 3.2 kJ/mol 239.7120 ± 0.0030 11094-39-6*0 Cyanoaminylium [HNCN]+ (g) 1363.2 1360.1 ± 2.5 kJ/mol 41.03157 ± 0.00082 205443-18-1*0 Cyanoamidogen anion [HNCN]- (g) 70.8 67.8 ± 1.4 kJ/mol 41.03267 ± 0.00082 67131-47-9*0 Ammonium radical NH4 (g) 190.01 179.42 ± 0.43 kJ/mol 18.03850 ± 0.00029 92075-50-8*0 Cyanamide NH2CN (g) 140.8 134.5 ± 1.5 kJ/mol 42.04006 ± 0.00082 420-04-2*0 Diazomethylene CNN (g) 579.3 580.0 ± 3.8 kJ/mol 40.02418 ± 0.00081 2468-81-7*0 Hydroperoxyimidogen HOON (g, trans) 103.3 99.8 ± 2.4 kJ/mol 47.01348 ± 0.00061 877456-58-1*1 Trichloromethylium [CCl3]+ (g) 854.35 852.84 ± 0.93 kJ/mol 118.3683 ± 0.0028 27130-34-3*0 Peroxychloric acid HOOCl(O)O (g) 77.5 69.3 ± 2.6 kJ/mol 100.4582 ± 0.0015 177778-91-5*0 Dichloromethyliumyl [CCl2]+ (g) 1121.6 1122.6 ± 1.8 kJ/mol 82.9156 ± 0.0020 55945-51-2*0 Tribromide [Br3]- (g) -287.4 -308.4 ± 1.9 kJ/mol 239.7125 ± 0.0030 14522-80-6*0 Cyanogen bromide anion [BrCN]- (g) 58.1 54.5 ± 3.8 kJ/mol 105.9220 ± 0.0013 54092-05-6*0 Hydrogen chloride HCl (aq, 2439 H2O) -166.712 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*951 Methyleneaminylium [CH2N]+ (g, triplet) 1456.6 1453.0 ± 2.1 kJ/mol 28.03277 ± 0.00082 53518-13-1*1 Imidogen anion [NH]- (g) 322.62 322.66 ± 0.16 kJ/mol 15.015229 ± 0.000099 23841-33-0*0 Methanimine cation [CH2NH]+ (g) 1056.1 1049.3 ± 1.8 kJ/mol 29.04071 ± 0.00083 65130-65-6*0 2-Cyclopropyn-1-ylidene C(CC) (g, singlet) 993.2 1000.1 ± 2.5 kJ/mol 36.0321 ± 0.0024 102508-15-6*2 Ethylene anion [CH2CH2]- (g, syn ?) 231.5 225.4 ± 2.0 kJ/mol 28.0537 ± 0.0016 34527-91-8*2 Hydrogen fluoride HF (aq, 23 H2O) -321.07 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*903 Nitric acid cation [HON(O)O]+ (g) 1029.14 1020.08 ± 0.69 kJ/mol 63.01233 ± 0.00091 272109-63-4*0 Triazirinylium ion [N(NN)]+ (g) 1608.9 1605.9 ± 1.6 kJ/mol 42.01967 ± 0.00021 92220-05-8*0 2-Propenylidyne anion [CH2CHC]- (g) 464.4 460.7 ± 1.7 kJ/mol 39.0565 ± 0.0024 120126-89-8*0 1-Ethylium-1-yl [CH3CH]+ (g) 1182.0 1174.6 ± 3.2 kJ/mol 28.0526 ± 0.0016 85944-79-2*0 Ethylidene anion [CH3CH]- (g) 325.6 318.3 ± 1.8 kJ/mol 28.0537 ± 0.0016 35829-99-3*0 Triazirine HN(NN) (g) 464.1 457.7 ± 2.6 kJ/mol 43.02816 ± 0.00022 157-29-9*0 Chloromethane cation [CH3Cl]+ (g) 1014.96 1008.19 ± 0.25 kJ/mol 50.4867 ± 0.0012 12538-71-5*0 Methanol anion [CH3OH]- (g) -89.1 -99.8 ± 2.8 kJ/mol 32.04241 ± 0.00090 68474-04-4*0 Methanimine anion [CH2NH]- (g) 224.4 217.2 ± 2.2 kJ/mol 29.04181 ± 0.00083 127593-73-1*0 2-Propen-3-yliumylidene [CHCHCH]+ (g) 1494.4 1491.4 ± 1.7 kJ/mol 39.0554 ± 0.0024 84654-86-4*0 Bromofluoromethane CH2FBr (g) -197.4 -211.9 ± 4.9 kJ/mol 112.9290 ± 0.0013 373-52-4*0 Hypochlorous acid cation [HOCl]+ (g) 998.91 995.87 ± 0.90 kJ/mol 52.45949 ± 0.00095 71606-47-8*0 Fluorodibromomethane CHFBr2 (g) -159.7 -179.3 ± 4.9 kJ/mol 191.8250 ± 0.0022 1868-53-7*0 2-Propenylidene anion [CHCHCH]- (g) 535.7 532.4 ± 1.7 kJ/mol 39.0565 ± 0.0024 98705-30-7*0 Difluorochlorobromomethane CF2ClBr (g) -428.9 -439.9 ± 4.9 kJ/mol 165.3642 ± 0.0016 353-59-3*0 Dichlorofluorobromomethane CCl2FBr (g) -228.3 -238.3 ± 4.9 kJ/mol 181.8185 ± 0.0022 353-58-2*0 Dibromofluorochloromethane CBr2FCl (g) -169.9 -186.8 ± 4.9 kJ/mol 226.2698 ± 0.0023 353-55-9*0 Krypton cation Kr+ (g) 1350.756 1350.756 ± 0.000 kJ/mol 83.7995 ± 0.1000 16915-28-9*0 Hypochlorous acid anion [HOCl]- (g) 198.7 198.4 ± 2.5 kJ/mol 52.46059 ± 0.00095 34524-94-2*0 Ammonium chloride (NH4)Cl (cr) -311.557 -314.718 ± 0.063 kJ/mol 53.49120 ± 0.00095 12125-02-9*510 Chloryl ion [OClO]+ (g) 1100.15 1097.49 ± 0.52 kJ/mol 67.4510 ± 0.0011 25052-55-5*0 2-Cyclopropyn-1-yl anion [C(CC)]- (g) 664.8 672.1 ± 1.6 kJ/mol 36.0326 ± 0.0024 500574-36-7*0 Chlorine difluoride cation [ClFF]+ (g) 1346.3 1344.9 ± 2.1 kJ/mol 73.44896 ± 0.00090 86825-59-4*0 Ammonium bromide (NH4)Br (cr) -253.41 -269.98 ± 0.17 kJ/mol 97.9425 ± 0.0010 12124-97-9*510 1,2-Difluoroacetylene cation [FCCF]+ (g) 1081.7 1084.5 ± 1.3 kJ/mol 62.0177 ± 0.0016 268566-70-7*0 Hydrogen chloride HCl (aq, 140 H2O) -165.946 ± 0.026 kJ/mol 36.46064 ± 0.00090 7647-01-0*907 Difluorophosgene cation [CF2O]+ (g) 653.45 650.69 ± 0.51 kJ/mol 66.00636 ± 0.00085 73256-56-1*0 Formaldehyde anion [CH2O]- (g) -26.7 -28.3 ± 2.0 kJ/mol 30.02653 ± 0.00087 27837-46-3*0 Triiodine cation [I3]+ (g) 946.1 941.0 ± 4.1 kJ/mol 380.712861 ± 0.000090 12596-32-6*0 Formaldehyde CH2O (g, triplet) 196.013 192.682 ± 0.097 kJ/mol 30.02598 ± 0.00087 50-00-0*1 Propynylidene HCCCH (g) 543.39 546.39 ± 0.63 kJ/mol 38.0480 ± 0.0024 67152-18-5*0 Chloro(chlorooxy)methylene ClCOCl (g, cis) 73.5 73.7 ± 3.6 kJ/mol 98.9155 ± 0.0020 479587-31-0*2 Chlorohydroxymethylene ClCOH (g, trans) 13.9 10.9 ± 2.6 kJ/mol 64.4707 ± 0.0012 147723-60-2*1 (Chlorooxy)methylene HCOCl (g, cis) 119.1 117.8 ± 2.7 kJ/mol 64.4707 ± 0.0012 331419-80-8*2 Dibromophosgene CBr2O (l) -144.12 ± 0.95 kJ/mol 187.8181 ± 0.0022 593-95-3*590 2-Chloroethanol ClCH2CH2OH (l) -314.92 ± 0.53 kJ/mol 80.5132 ± 0.0019 107-07-3*590 2-Bromoethanol BrCH2CH2OH (l) -274.57 ± 0.47 kJ/mol 124.9645 ± 0.0019 540-51-2*590 Water H2O (l, eq.press.) -285.831 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*589 Hydrogen fluoride HF (aq, 22.2 H2O) -321.06 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*888 Phenylium [C6H5]+ (g, singlet) 1148.42 1135.64 ± 0.85 kJ/mol 77.1034 ± 0.0048 17333-73-2*2 1-Cyclopropene-1,2-diyl CH2(CC) (g) 791.0 790.5 ± 1.5 kJ/mol 38.0480 ± 0.0024 202744-75-0*0 Nitrate [ON(O)O]- (aq) -206.64 ± 0.18 kJ/mol 62.00549 ± 0.00090 14797-55-8*800 m-Benzyne anion [C6H4]- (g) 444.0 435.1 ± 1.3 kJ/mol 76.0965 ± 0.0048 249589-31-9*0 p-Benzyne anion [C6H4]- (g) 465.0 455.4 ± 1.3 kJ/mol 76.0965 ± 0.0048 219298-17-6*0 Oxobromonium [BrO]+ (g) 1139.4 1131.7 ± 1.5 kJ/mol 95.9029 ± 0.0010 142315-39-7*0 Tetranitrogen cation [NNNN]+ (g) 1392.8 1392.5 ± 1.5 kJ/mol 56.02641 ± 0.00028 12185-04-5*0 Cycloheptane CH2(CH2CH2CH2CH2CH2C (cr,l) -126.90 -156.79 ± 0.51 kJ/mol 98.1861 ± 0.0057 291-64-5*500 Cyclopropenyliumdiyl [CH(CC)]+ (g) 1692.1 1695.0 ± 1.9 kJ/mol 37.0395 ± 0.0024 127476-05-5*0 Ethylbenzene C6H5CH2CH3 (cr,l) -12.56 ± 0.55 kJ/mol 106.1650 ± 0.0064 100-41-4*500 Phenylacetylene C6H5CCH (cr,l) 273.4 ± 1.1 kJ/mol 102.1332 ± 0.0064 536-74-3*500 Cyclopropynyl anion [CH(CC)]- (g) 518.08 521.07 ± 0.89 kJ/mol 37.0406 ± 0.0024 136861-42-2*0 Phenyloxoniumylidene [C6H5O]+ (g) 901.4 887.1 ± 2.2 kJ/mol 93.1028 ± 0.0048 41071-17-4*0 Anisole C6H5OCH3 (g) -47.81 -72.66 ± 0.80 kJ/mol 108.1378 ± 0.0056 100-66-3*0 Hydrogen fluoride HF (aq, 37 H2O) -321.13 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*890 Fluorobenzene C6H5F (cr,l) -151.81 -149.39 ± 0.89 kJ/mol 96.1023 ± 0.0048 462-06-6*500 Carbon atom C (g, triplet) 711.397 716.882 ± 0.047 kJ/mol 12.01070 ± 0.00080 7440-44-0*1 Acetylene anion [HCCH]- (g, cis ?) 380.1 380.3 ± 1.9 kJ/mol 26.0378 ± 0.0016 50443-89-5*2 Aminomethyliumyl [CHNH2]+ (g) 1039.5 1031.9 ± 2.3 kJ/mol 29.04071 ± 0.00083 89302-94-3*0 Fluorine atom cation F+ (g) 1758.310 1760.608 ± 0.048 kJ/mol 18.99785462 ± 0.00000050 14701-13-4*0 Bromobenzene C6H5Br (cr,l) 59.9 ± 1.3 kJ/mol 157.0079 ± 0.0049 108-86-1*500 Bromine dioxide OBrO (g) 167.1 157.5 ± 3.0 kJ/mol 111.9028 ± 0.0012 21255-83-4*0 Hydrogen fluoride HF (aq, 55.51 H2O) -321.17 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*891 Acetone CH3C(O)CH3 (cr,l) -245.06 -248.18 ± 0.36 kJ/mol 58.0791 ± 0.0025 67-64-1*500 Hypofluorous acid cation [HOF]+ (g) 1142.01 1138.99 ± 0.87 kJ/mol 36.00519 ± 0.00031 90243-22-4*0 Propionaldehyde CH3CH2CHO (cr,l) -218.18 -216.72 ± 0.29 kJ/mol 58.0791 ± 0.0025 123-38-6*500 Diazenium [NH2NH]+ (g) 968.56 957.30 ± 0.73 kJ/mol 31.03675 ± 0.00025 37369-93-0*0 trans-1,2-Dibromoethene CHBrCHBr (g, trans) 121.4 101.6 ± 2.1 kJ/mol 185.8453 ± 0.0026 590-12-5*0 1,1-Dibromoethene CH2CBr2 (g) 125.3 104.9 ± 2.2 kJ/mol 185.8453 ± 0.0026 593-92-0*0 Norbornadiene (CHCH)(CHCH2CH)(CHCH (g) 267.4 241.9 ± 1.0 kJ/mol 92.1384 ± 0.0056 121-46-0*0 Monoammonium succinate (CH2C(O)OH)2(NH3) (cr) -1067.97 ± 0.72 kJ/mol 135.1186 ± 0.0035 38457-08-8*510 Diammonium succinate (CH2COOH)2(NH3)2 (cr) -1182.52 ± 0.48 kJ/mol 152.1492 ± 0.0035 2226-88-2*510 Hydrogen chloride HCl (aq, 150 H2O) -165.979 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*829 Bicyclo[1.1.0]buta-1,3-diene-2,4-diyl C(CC)C (g) 1047.50 1055.09 ± 0.73 kJ/mol 48.0428 ± 0.0032 12184-80-4*0 Fluorosyl fluoride anion [FFO]- (g, quartet) -56.6 -55.7 ± 2.4 kJ/mol 53.99675 ± 0.00030 *86825-57-2*1 Acrolein CH2CHCHO (g, cis) -46.6 -56.9 ± 1.4 kJ/mol 56.0633 ± 0.0024 107-02-8*2 Ethenedione OCCO (g) 14.0 16.4 ± 2.3 kJ/mol 56.0202 ± 0.0017 4363-38-6*0 Ethenedione cation [OCCO]+ (g) 909.7 912.8 ± 2.3 kJ/mol 56.0197 ± 0.0017 12541-99-0*0 Methylammoniumyl [CH3NH2]+ (g) 865.81 851.88 ± 0.28 kJ/mol 31.05659 ± 0.00088 34516-31-9*0 Methylamine anion [CH3NH2]- (g) 84.1 69.3 ± 2.8 kJ/mol 31.05769 ± 0.00088 81096-79-9*0 Aminomethyl anion [CH2NH2]- (g) 209.4 199.1 ± 2.1 kJ/mol 30.04975 ± 0.00085 74215-21-7*0 Chlorine difluoride anion [ClFF]- (g) -319.0 -319.0 ± 2.2 kJ/mol 73.45005 ± 0.00090 91419-41-9*0 Hypofluorous acid anion [HOF]- (g, quartet) 155.3 154.7 ± 2.6 kJ/mol 36.00629 ± 0.00031 36505-07-4*2 Fluorosyl fluoride cation [FFO]+ (g, quartet) 1413.0 1413.4 ± 3.5 kJ/mol 53.99566 ± 0.00030 *86825-50-5*1 3-Imino-2-propen-1-ylidene CHCHCNH (g, anti-singlet) 532.9 527.8 ± 1.8 kJ/mol 53.0627 ± 0.0024 916765-05-4*12 Dioxodiazoxane ONONO (g, t, c) 109.3 105.2 ± 1.8 kJ/mol 76.01168 ± 0.00091 122413-35-8*2 3-Imino-2-propen-1-ylidene CHCHCNH (g, syn-triplet) 572.5 567.3 ± 2.0 kJ/mol 53.0627 ± 0.0024 916765-05-4*22 2-(Methylidyneamino)ethenyl CHCHNCH (g, syn-singlet) 604.4 599.6 ± 1.9 kJ/mol 53.0627 ± 0.0024 123416-74-0*12 2-(Methylidyneamino)ethenyl CHCHNCH (g, syn-triplet) 637.1 632.3 ± 2.0 kJ/mol 53.0627 ± 0.0024 123416-74-0*22 Peroxyhypochlorite [ClOO]- (g) -249.22 -248.20 ± 0.37 kJ/mol 67.4520 ± 0.0011 224299-14-3*0 1-Cyanovinylium [CH2CCN]+ (g) 1318.3 1317.1 ± 2.2 kJ/mol 52.0542 ± 0.0024 85399-09-3*0 Nirous oxide anion [NNO]- (g) 99.2 96.7 ± 1.9 kJ/mol 44.01343 ± 0.00033 12274-12-3*0 Carbon atom C (g, singlet) 833.328 838.475 ± 0.047 kJ/mol 12.01070 ± 0.00080 7440-44-0*2 Dioxygen O2 (g, triplet) -0.000 -0.000 ± 0.000 kJ/mol 31.99880 ± 0.00060 7782-44-7*1 Aminomethylene anion [CHNH2]- (g) 353.0 346.1 ± 2.3 kJ/mol 29.04181 ± 0.00083 207914-86-1*0 Tetraoxygen O4 (g, C2h singlet) 145.8 142.2 ± 3.8 kJ/mol 63.9976 ± 0.0012 12596-83-7*22 Hypobromous acid cation [HOBr]+ (g) 974.99 964.37 ± 0.53 kJ/mol 96.9108 ± 0.0010 154804-02-1*0 Tetrahedrane CH(CH(CHCH)) (g) 548.9 540.5 ± 1.5 kJ/mol 52.0746 ± 0.0032 157-39-1*0 Bromine atom Br (g, 2P3/2) 117.917 111.855 ± 0.056 kJ/mol 79.90400 ± 0.00100 10097-32-2*1 Cyanic azide NCNNN (g) 502.7 498.2 ± 1.9 kJ/mol 68.03766 ± 0.00085 764-05-6*0 Phenyl hydroperoxide C6H5OOH (g) 12.9 -6.1 ± 2.1 kJ/mol 110.1106 ± 0.0049 36112-26-2*0 Cyclopentene CH2(CH2CHCHCH2) (l) 4.41 ± 0.42 kJ/mol 68.1170 ± 0.0040 142-29-0*590 Methylcyclopentane CH3CH(CH2CH2CH2CH2) (cr,l) -116.74 -138.10 ± 0.38 kJ/mol 84.1595 ± 0.0049 96-37-7*500 1,2-Propadien-1-ylium-1-yl-3-ylidene [CCC]+ (g, lin) 1981.5 1989.4 ± 2.2 kJ/mol 36.0316 ± 0.0024 118090-85-0*1 Isopropylidene anion [CH3CCH3]- (g) 282.4 268.3 ± 2.0 kJ/mol 42.0803 ± 0.0024 *121408-19-3*0 NON cation [NON]+ (g) 1443.9 1444.1 ± 2.8 kJ/mol 44.01233 ± 0.00033 *227934-46-5*0 Dioxohydrazine ONNO (g, cis) 172.89 171.13 ± 0.14 kJ/mol 60.01228 ± 0.00062 16824-89-8*2 Dioxodiazoxane ONONO (g, c, p) 125.7 120.4 ± 2.1 kJ/mol 76.01168 ± 0.00091 122413-35-8*3 Acetic acid CH3C(O)OH (aq, 1000 H2O) -484.91 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*839 Trifluorine F3 (g) 80.6 81.9 ± 2.6 kJ/mol 56.9952096 ± 0.0000015 73455-86-4*0 Methyl acetate CH3C(O)OCH3 (l) -445.75 ± 0.61 kJ/mol 74.0785 ± 0.0025 79-20-9*500 Isoprene CH2C(CH3)CHCH2 (cr,l) 48.79 ± 0.69 kJ/mol 68.1170 ± 0.0040 78-79-5*500 Isodiazene anion [NNH2]- (g) 380.9 374.0 ± 2.1 kJ/mol 30.02991 ± 0.00020 *63986-30-1*0 Hydronium radical (H2O)(H) (g, vdW) -18.5 -21.6 ± 2.1 kJ/mol 19.02322 ± 0.00037 12168-76-2*100 Dihydrogen H2 (g, ortho) 1.417 0.019 ± 0.000 kJ/mol 2.01588 ± 0.00014 1333-74-0*1 Carbon dioxide anion [CO2]- (g) -340.6 -340.1 ± 2.2 kJ/mol 44.01005 ± 0.00100 14485-07-5*0 2-Hydroxyethenyl CHCHOH (g, cis-cis) 143.9 137.4 ± 1.1 kJ/mol 43.0446 ± 0.0016 108665-16-3*11 Isocyanic fluoride FNC (g) 301.3 303.1 ± 1.7 kJ/mol 45.01584 ± 0.00080 16992-26-0*0 2-Hydroxyethenyl CHCHOH (g, trans-trans) 147.2 140.9 ± 1.3 kJ/mol 43.0446 ± 0.0016 108665-16-3*22 Propionic acid CH3CH2C(O)OH (cr,l) -505.46 -509.61 ± 0.18 kJ/mol 74.0785 ± 0.0025 79-09-4*500 Ethylene glycol (CH2OH)2 (cr,l) -448.73 -455.25 ± 0.37 kJ/mol 62.0678 ± 0.0018 107-21-1*500 2-Hydroxyethenyl CHCHOH (g, cis-trans) 150.6 144.5 ± 1.6 kJ/mol 43.0446 ± 0.0016 108665-16-3*12 Ammonia anion [NH3]- (g) 94.3 87.2 ± 2.4 kJ/mol 17.03111 ± 0.00022 37353-00-7*0 Oxalic acid (C(O)OH)2 (cr) -819.57 -829.66 ± 0.42 kJ/mol 90.0349 ± 0.0020 144-62-7*500 Dimethylamine (CH3)2NH (l) -43.56 ± 0.38 kJ/mol 45.0837 ± 0.0017 124-40-3*500 Hydrogen bromide HBr (aq, 1000 H2O) -120.26 ± 0.15 kJ/mol 80.9119 ± 0.0010 10035-10-6*839 Hydrogen difluoride cation [(HF)(F)]+ (g, triplet) 1267.6 1265.4 ± 4.1 kJ/mol 39.004198 ± 0.000070 *126950-54-7*1 Trimethylamine (CH3)3N (l) -49.25 ± 0.98 kJ/mol 59.1103 ± 0.0025 75-50-3*500 Cyanogen anion [NCCN]- (g) 281.5 284.7 ± 2.2 kJ/mol 52.0354 ± 0.0016 11118-88-0*0 1,3-Propanediyl CH2CH2CH2 (g, triplet) 320.0 308.1 ± 1.6 kJ/mol 42.0797 ± 0.0024 32458-33-6*1 n-Heptane CH3(CH2)5CH3 (cr,l) -201.72 -224.17 ± 0.48 kJ/mol 100.2019 ± 0.0057 142-82-5*500 Diisocyanogen cation [CNNC]+ (g, trans) 1824.8 1827.5 ± 3.3 kJ/mol 52.0343 ± 0.0016 *78800-21-2*1 Isocyanogen chloride ClNC (g) 314.5 316.2 ± 2.4 kJ/mol 61.4701 ± 0.0012 75754-69-7*0 Cyanoaminyliumyl [NCN]+ (g) 1671.6 1672.9 ± 2.6 kJ/mol 40.02363 ± 0.00081 316122-03-9*0 Cyanoamidogen anion [NCN]- (g) 210.91 210.84 ± 0.77 kJ/mol 40.02473 ± 0.00081 189879-95-6*0 n-Octane CH3(CH2)6CH3 (cr,l) -226.66 -249.78 ± 0.67 kJ/mol 114.2285 ± 0.0065 111-65-9*500 1,5-Hexadiene CH2CHCH2CH2CHCH2 (cr,l) 54.43 ± 0.32 kJ/mol 82.1436 ± 0.0049 592-42-7*500 Cyanamide NH2CN (cr) 58.89 ± 0.54 kJ/mol 42.04006 ± 0.00082 420-04-2*500 Dioxiranylidene anion [C(OO)]- (g, ?) -110.2 -109.7 ± 3.0 kJ/mol 44.01005 ± 0.00100 *138832-58-3*0 Diazomethyliumyl [CNN]+ (g) 1641.2 1642.4 ± 4.1 kJ/mol 40.02363 ± 0.00081 307495-90-5*0 Diazomethylene anion [CNN]- (g) 408.3 408.5 ± 3.8 kJ/mol 40.02473 ± 0.00081 205498-92-6*0 3H-Diazirin-3-ylidene C(NN) (g) 578.8 579.2 ± 2.7 kJ/mol 40.02418 ± 0.00081 253308-70-2*0 Dioxygen difluoride OOF2 (g) 75.1 71.6 ± 3.6 kJ/mol 69.99561 ± 0.00060 183051-89-0*0 Trioxidanyl HOOO (g) 25.32 23.23 ± 0.13 kJ/mol 49.00614 ± 0.00090 12500-78-6*0 Ethynylene C2 (g, triplet) 827.55 834.25 ± 0.26 kJ/mol 24.0214 ± 0.0016 12070-15-4*1 Chloromethyliumylidene [CCl]+ (g) 1282.6 1285.7 ± 2.4 kJ/mol 47.4629 ± 0.0012 69773-94-0*0 Chloromethylidyne anion [CCl]- (g) 319.7 323.4 ± 2.5 kJ/mol 47.4639 ± 0.0012 117129-77-8*0 Isocyanogen bromide BrNC (g) 341.4 335.7 ± 3.4 kJ/mol 105.9214 ± 0.0013 65997-98-0*0 Dihydrogen fluoride (HF)(H) (g) -56.5 -54.1 ± 1.7 kJ/mol 21.01428 ± 0.00014 12592-22-2*2 1-Propynylium [CH3CC]+ (g) 1547.0 1545.1 ± 3.1 kJ/mol 39.0554 ± 0.0024 24858-94-4*0 Bromoniumyl [HBr]+ (g) 1098.01 1090.17 ± 0.15 kJ/mol 80.9114 ± 0.0010 12258-64-9*0 Tetraoxodinitrogen cation [O2NNO2]+ (g) 1030.6 1025.1 ± 2.6 kJ/mol 92.0105 ± 0.0012 64476-91-1*0 Trihydrogen H(HH) (g, 2p 2A2" Ry) 756.931 754.146 ± 0.015 kJ/mol 3.02382 ± 0.00021 12184-91-7*2 Cycloprop-1-enylium [CH2(CHC)]+ (g) 1502.2 1497.9 ± 2.2 kJ/mol 39.0554 ± 0.0024 117067-78-4*0 Hydrochlorate ion [HCl]- (g) -25.2 -24.2 ± 2.5 kJ/mol 36.46119 ± 0.00090 63099-75-2*0 1,1,1-Trichloroethane CH3CCl3 (l) -177.54 ± 0.49 kJ/mol 133.4033 ± 0.0031 71-55-6*500 Cycloprop-1-enylide [CH2(CHC)]- (g) 373.4 369.0 ± 2.2 kJ/mol 39.0565 ± 0.0024 80251-77-0*0 Acetonitrile CH3CN (cr,l) 40.59 ± 0.23 kJ/mol 41.0520 ± 0.0016 75-05-8*500 Isocyanogen iodide INC (g) 341.7 342.0 ± 4.9 kJ/mol 152.92191 ± 0.00080 66004-32-8*0 Cycloprop-2-enylide [CH(CHCH)]- (g) 514.8 511.8 ± 2.2 kJ/mol 39.0565 ± 0.0024 20829-57-6*0 Isocyanogen iodide anion [INC]- (g) 123.0 125.2 ± 9.3 kJ/mol 152.92246 ± 0.00080 *66004-32-8*0 Dioxymethylidyne cation [COO]+ (g, doublet) 1436.6 1439.0 ± 2.7 kJ/mol 44.00895 ± 0.00100 *791121-04-5*2 Vinyl chloride CH2CHCl (cr,l) -2.7 1.9 ± 1.9 kJ/mol 62.4979 ± 0.0018 75-01-4*500 Poly(vinylchloride) CH2CHCl (s, poly) -84.6 -94.0 ± 1.3 kJ/mol 62.4979 ± 0.0018 9002-86-2*500 1,1-Dichloroethene CH2CCl2 (l) -23.80 ± 0.50 kJ/mol 96.9427 ± 0.0024 75-35-4*500 Chlorine chlorite ClOClO (g, cis) 177.4 175.0 ± 2.2 kJ/mol 102.9042 ± 0.0019 105206-44-8*2 Perchloryl cation [OCl(O)O]+ (g) 1252.1 1246.3 ± 2.5 kJ/mol 83.4504 ± 0.0013 23594-88-9*0 Dihydrogen cation [H2]+ (g, ortho) 1489.060 1488.480 ± 0.000 kJ/mol 2.01533 ± 0.00014 12184-90-6*1 Hydrogen fluoride HF (aq, 18.5 H2O) -321.03 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*887 Dichloromethane CH2Cl2 (l) -122.42 ± 0.54 kJ/mol 84.9320 ± 0.0020 75-09-2*590 Hydrogen chloride HCl (aq, 3000 H2O) -166.741 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*842 Methanol dimer (CH3OH)2 (g) -398.5 -419.2 ± 1.4 kJ/mol 64.0837 ± 0.0018 42845-44-3*0 Dioxymethylidyne cation [(C)(OO)]+ (g, vdW quartet) 1388.2 1391.7 ± 3.2 kJ/mol 44.00895 ± 0.00100 *791121-04-5*101 Difluoromethylene anion [CF2]- (g) -211.17 -209.99 ± 0.60 kJ/mol 50.00805 ± 0.00080 66212-40-6*0 Fluoromethylidyne anion [CF]- (g) 200.8 204.3 ± 1.9 kJ/mol 31.00965 ± 0.00080 33412-12-3*0 Cyclopropenylidene anion [C(CHCH)]- (g) 544.2 543.8 ± 2.2 kJ/mol 38.0485 ± 0.0024 *16165-40-5*0 Tetraoxidanyl HOOOO (g, cis) 53.0 46.0 ± 5.1 kJ/mol 65.0055 ± 0.0012 69696-93-1*2 Difluorovinylidene CCF2 (g) 129.4 130.7 ± 2.2 kJ/mol 62.0182 ± 0.0016 41895-33-4*0 Nitric acid HON(O)O (aq, 1 H2O) -186.85 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*801 Fluoroethynylium [CCF]+ (g) 1536.2 1540.9 ± 2.3 kJ/mol 43.0193 ± 0.0016 268566-69-4*0 Peroxychlorous acid HOOClO (g, anti) 103.5 97.6 ± 2.5 kJ/mol 84.4588 ± 0.0013 177778-92-6*2 Bromoacetylene HCCBr (g) 282.1 275.6 ± 1.6 kJ/mol 104.9333 ± 0.0019 593-61-3*0 Nitric acid HON(O)O (aq, 3 H2O) -197.76 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*805 2-Oxo-1-ethylium-1-yl [HCC(O)H]+ (g, anti-quartet) 1289.4 1286.0 ± 2.5 kJ/mol 42.0361 ± 0.0016 214464-96-7*11 Oxoethylidene anion [HCC(O)H]- (g, anti-gauche) 86.9 83.6 ± 2.1 kJ/mol 42.0372 ± 0.0016 106543-38-8*1 Chloro(chlorooxy)methylene ClCOCl (g, trans singlet) 98. 101. ± 15. kJ/mol 98.9155 ± 0.0020 479587-31-0*11 Paraformaldehyde CH2O (cr, paraformaldehyde) -179.2 ± 1.6 kJ/mol 30.02598 ± 0.00087 30525-89-4*500 Chlorooxomethylium [ClCO]+ (g) 783.7 783.9 ± 2.2 kJ/mol 63.4623 ± 0.0012 38264-03-8*0 Tetrazete N(NNN) (g, D2h) 764.9 759.0 ± 1.8 kJ/mol 56.02696 ± 0.00028 42851-09-2*0 Oxygen atom hexacation [O]+6 (g) 42035.28 42037.14 ± 0.12 kJ/mol 15.99611 ± 0.00030 14158-22-6*0 2-Iodoethanol ICH2CH2OH (l) -207.2 ± 2.4 kJ/mol 171.9650 ± 0.0017 624-76-0*590 Tetraazatetrahedrane N(N(N)N) (g, Td) 763.7 757.2 ± 1.7 kJ/mol 56.02696 ± 0.00028 12596-63-3*0 1,3-Butadiyne cation [HCCCCH]+ (g) 1439.72 1441.58 ± 0.80 kJ/mol 50.0581 ± 0.0032 55468-55-8*0 Hydrogen difluoride cation [FHF]+ (g, triplet ?) 1241. 1238. ± 17. kJ/mol 39.004198 ± 0.000070 126950-54-7*1 Carbon suboxide cation [OCCCO]+ (g) 928.3 931.8 ± 1.3 kJ/mol 68.0304 ± 0.0025 151528-67-5*0 Carbon suboxide anion [OCCCO]- (g) -131.4 -128.0 ± 2.5 kJ/mol 68.0314 ± 0.0025 109362-94-9*0 Benzene anion [C6H6]- (g) 209.1 197.2 ± 1.2 kJ/mol 78.1124 ± 0.0048 34562-85-1*0 Nitric acid trihydrate (HON(O)O)(H2O)3 (cr,l) -1062.10 -1055.25 ± 0.21 kJ/mol 117.0587 ± 0.0019 13444-83-2*500 o-Benzyne C6H4 (g, triplet) 625.5 616.2 ± 1.1 kJ/mol 76.0960 ± 0.0048 462-80-6*1 Nitric acid monohydrate (HON(O)O)(H2O) (cr,l) -479.18 -472.68 ± 0.19 kJ/mol 81.0282 ± 0.0012 13444-82-1*500 Dioxiranylidene cation [C(OO)]+ (g) 1409.1 1410.3 ± 2.6 kJ/mol 44.00895 ± 0.00100 *138832-57-2*0 2-Propen-3-ylium-1-ylidyne [CHCHC]+ (g) 1791.1 1792.7 ± 2.6 kJ/mol 38.0474 ± 0.0024 161054-36-0*0 Ethyl hydroperoxide CH3CH2OOH (cr,l) -205. ± 21. kJ/mol 62.0678 ± 0.0018 3031-74-1*500 m-Benzyne C6H4 (g) 526.9 518.4 ± 1.2 kJ/mol 76.0960 ± 0.0048 1828-89-3*0 Propenediylidene anion [CHCHC]- (g) 588.8 590.0 ± 2.3 kJ/mol 38.0485 ± 0.0024 *161054-36-0*0 p-Benzyne cation [C6H4]+ (g) 1424.8 1417.6 ± 2.1 kJ/mol 76.0954 ± 0.0048 121058-09-1*0 p-Benzyne C6H4 (g) 586.9 577.5 ± 1.2 kJ/mol 76.0960 ± 0.0048 3355-34-8*0 Toluene C6H5CH3 (l) 19.72 11.97 ± 0.34 kJ/mol 92.1384 ± 0.0056 108-88-3*500 Cyclopentadienylium [CH(CHCHCHCH)]+ (g) 1087.60 1074.73 ± 0.92 kJ/mol 65.0927 ± 0.0040 29661-18-5*0 Triiodine I3 (g) 153.4 149.4 ± 3.6 kJ/mol 380.713410 ± 0.000090 12596-31-5*0 Hydraziniumyl [NH2NH2]+ (g) 886.6 873.2 ± 2.0 kJ/mol 32.04469 ± 0.00031 20771-51-1*0 Cycloheptene CH2(CHCHCH2CH2CH2CH2 (cr,l) -25.5 -46.6 ± 1.7 kJ/mol 96.1702 ± 0.0057 628-92-2*500 Hydroxylamine NH2OH (aq, undissoc) -97.1 ± 2.2 kJ/mol 33.02996 ± 0.00037 7803-49-8*1000 Cycloheptatriene CH2(CHCHCHCHCHCH) (cr,l) 153.74 144.95 ± 0.97 kJ/mol 92.1384 ± 0.0056 544-25-2*500 1-Propenylium [CH3CHCH]+ (g, cis) 1231.9 1221.6 ± 1.7 kJ/mol 41.0713 ± 0.0024 50457-58-4*2 Nitrosyl nitrite anion [ONONO]- (g, t, t) -103.1 -106.2 ± 2.8 kJ/mol 76.01223 ± 0.00091 *122413-35-8*1 Phenylethene C6H5CHCH2 (cr,l) 104.30 ± 0.48 kJ/mol 104.1491 ± 0.0064 100-42-5*500 Hydrazine NH2NH2 (cr,l) 57.25 50.68 ± 0.18 kJ/mol 32.04524 ± 0.00031 302-01-2*500 Phenol C6H5OH (cr,l) -146.55 -162.39 ± 0.65 kJ/mol 94.1112 ± 0.0048 108-95-2*500 Formic acid HC(O)OH (cr,l) -431.56 -424.72 ± 0.20 kJ/mol 46.0254 ± 0.0010 64-18-6*500 1-Propenylide [CH3CHCH]- (g, cis) 204.1 192.8 ± 1.8 kJ/mol 41.0723 ± 0.0024 65887-20-9*2 Anisole C6H5OCH3 (l) -119.58 ± 0.77 kJ/mol 108.1378 ± 0.0056 100-66-3*500 Peroxynitrous acid HOONO (g) -5.81 -11.64 ± 0.36 kJ/mol 63.01288 ± 0.00091 14691-52-2*0 Benzaldehyde C6H5C(O)H (cr,l) -85.8 -86.8 ± 1.1 kJ/mol 106.1219 ± 0.0056 100-52-7*500 (Z)-Diazene anion [HNNH]- (g, cis) 280.0 273.3 ± 2.0 kJ/mol 30.02991 ± 0.00020 *86631-37-0*0 Fluorobenzene anion [C6H5F]- (g) -18.3 -30.2 ± 1.8 kJ/mol 96.1029 ± 0.0048 34561-55-2*0 m-Chlorophenylium [C6H4Cl]+ (g) 1159.9 1149.8 ± 2.6 kJ/mol 111.5481 ± 0.0049 127983-85-1*0 p-Chlorophenylium [C6H4Cl]+ (g) 1147.2 1137.7 ± 2.5 kJ/mol 111.5481 ± 0.0049 42766-43-8*0 o-Chlorophenylium [C6H4Cl]+ (g) 1166.5 1157.2 ± 2.5 kJ/mol 111.5481 ± 0.0049 137963-70-3*0 Hydroxyoxoammoniumyl [HONO]+ (g, trans) 984.1 977.7 ± 1.8 kJ/mol 47.01293 ± 0.00061 80371-48-8*1 Iodobenzene cation [C6H5I]+ (g) 1022.69 1007.25 ± 0.99 kJ/mol 204.0078 ± 0.0048 38406-85-8*0 1-Ethenylium-1-yl [CCH2]+ (g) 1507.0 1507.1 ± 2.1 kJ/mol 26.0367 ± 0.0016 80541-07-7*0 Carbon dioxide cation [CO2]+ (g, quartet) 1335.0 1335.5 ± 2.4 kJ/mol 44.00895 ± 0.00100 12181-61-2*1 Nitrobenzene C6H5N(O)O (cr,l) 6.4 ± 1.4 kJ/mol 123.1094 ± 0.0049 98-95-3*500 Nitromethane CH3N(O)O (cr,l) -114.17 -112.98 ± 0.43 kJ/mol 61.0401 ± 0.0010 75-52-5*500 Peroxyhypochlorous acid cation [HOOCl]+ (g, trans) 1030.3 1024.5 ± 2.5 kJ/mol 68.4589 ± 0.0011 *67952-07-2*1 Hydrogen fluoride HF (aq, 400 H2O) -321.47 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*832 2,2,4-Trimethylpentane (CH3)2CHCH2C(CH3)3 (cr,l) -224.5 -258.9 ± 1.5 kJ/mol 114.2285 ± 0.0065 540-84-1*500 Formyloxidanyl HC(O)O (g) -125.91 -127.27 ± 0.56 kJ/mol 45.0174 ± 0.0010 16499-21-1*0 Norbornadiene (CHCH)(CHCH2CH)(CHCH (l) 208.6 ± 1.2 kJ/mol 92.1384 ± 0.0056 121-46-0*500 2,3-Butanedione CH3C(O)C(O)CH3 (cr,l) -365.66 ± 0.53 kJ/mol 86.0892 ± 0.0033 431-03-8*500 Succinic acid (CH2C(O)OH)2 (g) -802.9 -825.1 ± 3.0 kJ/mol 118.0880 ± 0.0034 110-15-6*0 Dioxiranyl HC(OO) (g) 217.3 213.8 ± 2.0 kJ/mol 45.0174 ± 0.0010 120595-16-6*0 NON anion [NON]- (g) 495.3 492.8 ± 2.5 kJ/mol 44.01343 ± 0.00033 *227934-47-6*0 1,2-Diiodoethane CH2ICH2I (g) 87.79 73.13 ± 0.90 kJ/mol 281.8621 ± 0.0016 624-73-7*0 1,2-Diiodoethane CH2ICH2I (cr,l) 9.26 ± 0.60 kJ/mol 281.8621 ± 0.0016 624-73-7*500 Helium hydride cation [HeH]+ (g) 1350.148 1348.258 ± 0.000 kJ/mol 5.009993 ± 0.000070 17009-49-3*0 Xenon hydride cation [XeH]+ (g) 1038.03 1036.26 ± 0.89 kJ/mol 132.2974 ± 0.0200 37276-91-8*0 2-Butanone CH3CH2C(O)CH3 (cr,l) -267.90 -273.39 ± 0.79 kJ/mol 72.1057 ± 0.0033 78-93-3*500 2,4,5-Trioxa-1,3-diazabicyclo[1.1.1]pentane N(O3)N (g) 602.5 593.3 ± 2.1 kJ/mol 76.01168 ± 0.00091 224950-18-9*0 Cyclopropylium [CH(CH2CH2)]+ (g) 1104.5 1093.0 ± 2.5 kJ/mol 41.0713 ± 0.0024 1724-43-2*0 Hydrazoic acid cation [HNNN]+ (g) 1333.66 1327.99 ± 0.83 kJ/mol 43.02761 ± 0.00022 58852-14-5*0 Acrolein CH2CHCHO (cr,l) -95.8 ± 1.4 kJ/mol 56.0633 ± 0.0024 107-02-8*500 Hydrazoic acid anion [HNNN]- (g, trans) 309.0 302.7 ± 2.3 kJ/mol 43.02871 ± 0.00022 203264-98-6*1 Ethenedione anion [OCCO]- (g) -148.4 -145.8 ± 2.4 kJ/mol 56.0207 ± 0.0017 77783-15-4*0 Hydrogen chloride HCl (aq, 200 H2O) -166.105 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*830 Urea NH2C(O)NH2 (cr,l) -317.79 -333.38 ± 0.12 kJ/mol 60.05534 ± 0.00091 57-13-6*500 Formamide CH(O)NH2 (cr,l) -251.01 ± 0.29 kJ/mol 45.04066 ± 0.00088 75-12-7*500 Peroxyhypochlorous acid anion [HOOCl]- (g, cis quartet) -32.2 -34.0 ± 2.6 kJ/mol 68.4600 ± 0.0011 *67952-08-3*2 Acetamide CH3C(O)NH2 (cr,l) -315.78 ± 0.56 kJ/mol 59.0672 ± 0.0017 60-35-5*500 Ethoxyethane CH3CH2OCH2CH3 (cr,l) -265.43 -277.74 ± 0.82 kJ/mol 74.1216 ± 0.0033 60-29-7*500 Trioxidane HOOOH (g) -82.01 -90.61 ± 0.63 kJ/mol 50.01408 ± 0.00091 14699-99-1*0 Acrylonitrile CH2CHCN (g, triplet) 446.3 440.9 ± 1.8 kJ/mol 53.0627 ± 0.0024 107-13-1*2 Acrylonitrile CH2CHCN (cr,l) 146.26 153.92 ± 0.78 kJ/mol 53.0627 ± 0.0024 107-13-1*500 Isocyanoethene CH2CHNC (g, triplet) 544.0 539.1 ± 1.8 kJ/mol 53.0627 ± 0.0024 14668-82-7*2 Cyclobutane CH2(CH2CH2CH2) (l) 3.90 ± 0.40 kJ/mol 56.1063 ± 0.0032 287-23-0*590 Bromosyl bromide BrBrO (g) 179.0 163.2 ± 2.1 kJ/mol 175.8074 ± 0.0020 68322-97-4*0 1-Isocyanoethylidene CH3CNC (g) 527.7 523.0 ± 1.1 kJ/mol 53.0627 ± 0.0024 *498544-34-6*0 Nitrous acid anion [HONO]- (g, cis) -105.85 -110.48 ± 0.78 kJ/mol 47.01403 ± 0.00061 256393-36-9*2 Methylcyclopropane CH3CH(CH2CH2) (l) 1.83 ± 0.59 kJ/mol 56.1063 ± 0.0032 594-11-6*590 Carbon monoxide anion [CO]- (g) 30.0 33.7 ± 2.3 kJ/mol 28.01065 ± 0.00085 12539-63-8*0 Methylamine CH3NH2 (l) -45.36 ± 0.46 kJ/mol 31.05714 ± 0.00088 74-89-5*500 Trioxirane O(OO) (g) 272.7 270.1 ± 1.3 kJ/mol 47.99820 ± 0.00090 153851-84-4*0 Deuterium hydride HD (g) 0.328 0.319 ± 0.000 kJ/mol 3.022042 ± 0.000070 13983-20-5*0 1-Methyl-1-ethylium-1-yl [CH3CCH3]+ (g) 1058.1 1045.6 ± 1.9 kJ/mol 42.0792 ± 0.0024 121408-19-3*0 Iodine monochloride ICl (cr) -36.511 -35.537 ± 0.063 kJ/mol 162.35717 ± 0.00090 7790-99-0*510 Carbon monoxide CO (g, triplet) 465.579 469.286 ± 0.026 kJ/mol 28.01010 ± 0.00085 630-08-0*1 Chlorodioxidenium [ClOO]+ (g) 1202.7 1200.4 ± 3.4 kJ/mol 67.4510 ± 0.0011 64710-10-7*0 Oxygen difluoride cation [FOF]+ (g) 1292.12 1289.59 ± 0.66 kJ/mol 53.99566 ± 0.00030 39432-25-2*0 Azide [NNN]- (aq) 272.63 ± 0.48 kJ/mol 42.02077 ± 0.00021 14343-69-2*800 Propane cation [CH3CH2CH3]+ (g) 974.6 954.7 ± 1.7 kJ/mol 44.0951 ± 0.0025 34479-70-4*0 Tetraoxygen O4 (g, C2h triplet) 104.4 102.4 ± 3.5 kJ/mol 63.9976 ± 0.0012 12596-83-7*11 Hydrogen peroxide H2O2 (cr,l) -193.171 -187.354 ± 0.079 kJ/mol 34.01468 ± 0.00062 7722-84-1*500 Cyclobutenylium [CH2(CHCHCH)]+ (g) 1036.9 1023.8 ± 3.4 kJ/mol 53.0820 ± 0.0032 12316-90-4*0 Difluorodioxidanium [FOOF]+ (g, trans) 1283.6 1279.1 ± 2.3 kJ/mol 69.99506 ± 0.00060 *7783-44-0*1 Butyraldehyde CH3CH2CH2CHO (cr,l) -235.99 -239.51 ± 0.84 kJ/mol 72.1057 ± 0.0033 123-72-8*500 Oxadiazirine cation [O(NN)]+ (g) 1509.9 1507.2 ± 2.4 kJ/mol 44.01233 ± 0.00033 *227934-45-4*0 Oxygen difluoride anion [FOF]- (g) -202.0 -201.9 ± 2.7 kJ/mol 53.99675 ± 0.00030 *7783-41-7*0 Chlorine hydride oxide HCl(O)(O)O (g) 165.1 155.3 ± 2.5 kJ/mol 84.4588 ± 0.0013 1027055-52-2*0 Silicon carbide SiC (g) 735.6 740.6 ± 2.5 kJ/mol 40.09620 ± 0.00085 409-21-2*0 Silicon carbide SiC (cr, beta-cubic) -72.3 -73.3 ± 1.5 kJ/mol 40.09620 ± 0.00085 409-21-2*502 Quartz SiO2 (cr,l) -906.11 -911.09 ± 0.94 kJ/mol 60.08430 ± 0.00067 14808-60-7*500 Quartz SiO2 (vitr) -825.67 -901.59 ± 0.95 kJ/mol 60.08430 ± 0.00067 14808-60-7*520 Hydrogen chloride HCl (aq, 1000 H2O) -166.565 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*839 Quartz SiO2 (cr, beta-cristobalite) -903.41 -908.27 ± 0.98 kJ/mol 60.08430 ± 0.00067 14808-60-7*510 Nitrosyl nitrate ONONO2 (g, cis-perp) 60.4 52.5 ± 1.9 kJ/mol 92.0111 ± 0.0012 15969-55-8*2 Methylene CH2 (g) 391.060 391.617 ± 0.097 kJ/mol 14.02658 ± 0.00081 2465-56-7*0 Tetrabromomethane CBr4 (cr, monoclinic) 49.3 ± 1.4 kJ/mol 331.6267 ± 0.0041 558-13-4*500 Propionic acid CH3CH2C(O)OH (g) -436.41 -454.30 ± 0.60 kJ/mol 74.0785 ± 0.0025 79-09-4*0 Tetraiodomethane CI4 (cr, monoclinic) 392.5 ± 8.0 kJ/mol 519.62858 ± 0.00081 507-25-5*500 1-Hydroxyethyl CH3CHOH (g) -42.76 -56.19 ± 0.58 kJ/mol 45.0605 ± 0.0017 2348-46-1*0 Bromomethane CH3Br (l) -55.99 -59.01 ± 0.27 kJ/mol 94.9385 ± 0.0013 74-83-9*590 Acetic acid CH3C(O)OH (aq, 500 H2O) -484.89 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*833 Tetroxidane HOOOOH (g) -34.1 -44.6 ± 2.3 kJ/mol 66.0135 ± 0.0012 29683-94-1*0 Water H2O (g, para) -238.932 -241.835 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*2 1-Methylethenylium [CH3CCH2]+ (g) 995.2 986.0 ± 2.0 kJ/mol 41.0713 ± 0.0024 50457-57-3*0 Tetraoxodinitrate anion [O2NNO2]- (g) -184.6 -187.8 ± 2.4 kJ/mol 92.0116 ± 0.0012 63552-02-3*0 Trihydrogen (H)(HH) (g, vdW) 215.9 218.3 ± 1.1 kJ/mol 3.02382 ± 0.00021 12184-91-7*100 Acetic acid CH3C(O)OH (aq, 10000 H2O) -484.94 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*850 Oxygen atom octacation [O]+8 (g) 197447.75 197449.60 ± 0.12 kJ/mol 15.99501 ± 0.00030 21450-98-6*0 Dinitrogen dimer (N2)2 (g) -0.88 0.84 ± 0.67 kJ/mol 56.02696 ± 0.00028 154680-01-0*0 Ammonium hydroxide NH4OH (aq, undissoc) -366.716 ± 0.062 kJ/mol 35.04584 ± 0.00047 1336-21-6*1000 Cyclopropane cation [CH2(CH2CH2)]+ (g) 1022.3 1006.8 ± 1.6 kJ/mol 42.0792 ± 0.0024 34496-93-0*0 1-Propen-1-yl-3-ylidene CHCHCH (g, quartet) 656.6 653.2 ± 1.1 kJ/mol 39.0559 ± 0.0024 84654-90-0*1 Trioxirane cation [O(OO)]+ (g) 1444.5 1442.3 ± 2.2 kJ/mol 47.99765 ± 0.00090 *153851-84-4*0 mu-Oxodichlorine cation [ClOCl]+ (g) 1130.44 1126.83 ± 0.63 kJ/mol 86.9043 ± 0.0018 51174-96-0*0 Ethyl bromide CH3CH2Br (l) -55.56 -91.09 ± 0.26 kJ/mol 108.9651 ± 0.0019 74-96-4*500 Dihydrogen anion [H2]- (g) 253.8 254.7 ± 1.2 kJ/mol 2.01643 ± 0.00014 12184-89-3*0 Vinyl iodide CH2CHI (g) 139.5 130.7 ± 1.2 kJ/mol 153.9497 ± 0.0016 593-66-8*0 Hydrogen peroxide H2O2 (g, para) -129.479 -135.465 ± 0.063 kJ/mol 34.01468 ± 0.00062 7722-84-1*2 iso-Hexane CH3CH2CH2CH(CH3)2 (cr,l) -180.35 -204.01 ± 0.83 kJ/mol 86.1754 ± 0.0049 107-83-5*500 Chlorine trifluoride cation [FCl(F)F]+ (g) 1053.4 1049.1 ± 2.5 kJ/mol 92.44736 ± 0.00090 478167-77-0*0 Difluorovinylidene cation [CCF2]+ (g) 1181.6 1183.0 ± 2.3 kJ/mol 62.0177 ± 0.0016 268566-71-8*0 1-Methylethenyl anion [CH3CCH2]- (g) 199.4 188.2 ± 2.0 kJ/mol 41.0723 ± 0.0024 65887-19-6*0 Methyl acetate CH3C(O)OCH3 (g) -394.29 -413.16 ± 0.61 kJ/mol 74.0785 ± 0.0025 79-20-9*0 Oxygen atom heptacation [O]+7 (g) 113369.48 113371.34 ± 0.12 kJ/mol 15.99556 ± 0.00030 14274-89-6*0 2-Oxo-1-ethylium-1-yl [HCC(O)H]+ (g, syn-quartet) 1292.0 1288.6 ± 2.4 kJ/mol 42.0361 ± 0.0016 214464-96-7*12 Peroxyformate [HC(O)OO]- (g, anti) -320.8 -326.7 ± 1.8 kJ/mol 61.0174 ± 0.0012 104960-05-6*2 Hypochloroperoxoous acid, hydroxy ester HOOOCl (g, anti) 49.5 42.5 ± 2.5 kJ/mol 84.4588 ± 0.0013 928652-99-7*2 Oxoethylidene anion [HCC(O)H]- (g, syn-gauche) 92.2 89.0 ± 2.3 kJ/mol 42.0372 ± 0.0016 106543-38-8*2 Polyoxymethylene CH2O (cr, polyoxymethylene) -170.88 ± 0.21 kJ/mol 30.02598 ± 0.00087 9002-81-7*500 Peroxyformyl HC(O)OO (g, anti) -90.6 -96.0 ± 1.8 kJ/mol 61.0168 ± 0.0012 56240-83-6*2 1,2-Propadien-1-ylium-1-yl-3-ylidene [CCC]+ (g) 1944.7 1952.6 ± 1.9 kJ/mol 36.0316 ± 0.0024 118090-85-0*0 Nitrogen atom N (g, quartet) 470.579 472.442 ± 0.024 kJ/mol 14.006740 ± 0.000070 17778-88-0*1 Chloro(chlorooxy)methylene ClCOCl (g, trans triplet) 101.1 104.7 ± 4.8 kJ/mol 98.9155 ± 0.0020 479587-31-0*12 Oxygen atom trication [O]+3 (g) 10249.929 10252.880 ± 0.018 kJ/mol 15.99775 ± 0.00030 14127-64-1*0 Dihydrogen cation [H2]+ (g, para) 1488.364 1488.480 ± 0.000 kJ/mol 2.01533 ± 0.00014 12184-90-6*2 Carbon suboxide OCCCO (cr,l) -131.7 -116.6 ± 1.3 kJ/mol 68.0309 ± 0.0025 504-64-3*500 Formaldehyde CH2O (aq) -171.19 ± 0.59 kJ/mol 30.02598 ± 0.00087 50-00-0*800 Trioxygen difluoride FOOOF (g) 112.2 107.1 ± 1.1 kJ/mol 85.99501 ± 0.00090 16829-28-0*0 Isocyanogen cation [CNCN]+ (g) 1653.1 1655.4 ± 1.6 kJ/mol 52.0343 ± 0.0016 133415-63-1*0 m-Benzyne C6H4 (g, triplet) 614.5 605.1 ± 1.4 kJ/mol 76.0960 ± 0.0048 1828-89-3*1 Diisocyanogen cation [CNNC]+ (g, cis) 1838.1 1842.0 ± 3.1 kJ/mol 52.0343 ± 0.0016 *78800-21-2*2 Oxonium [H3O]+ (g, para) 605.85 599.10 ± 0.17 kJ/mol 19.02267 ± 0.00037 13968-08-6*2 Iodine monochloride ICl (l) -24.048 ± 0.063 kJ/mol 162.35717 ± 0.00090 7790-99-0*590 Tropylide [CH(CHCHCHCHCHCH)]- (g) 260.9 244.6 ± 2.0 kJ/mol 91.1310 ± 0.0056 34464-18-1*0 Difluorine cation [F2]+ (g) 1514.301 1514.475 ± 0.013 kJ/mol 37.9962578 ± 0.0000010 12184-86-0*0 Dihydrogen H2 (g, para) -0.000 -0.058 ± 0.000 kJ/mol 2.01588 ± 0.00014 1333-74-0*2 Fluorine atom F (g, 2P3/2) 77.262 79.047 ± 0.048 kJ/mol 18.99840320 ± 0.00000050 14762-94-8*1 Propylene cation [CH3CHCH2]+ (g) 975.18 961.65 ± 0.20 kJ/mol 42.0792 ± 0.0024 34504-10-4*0 Deuteride D- (g) 146.991 148.904 ± 0.0021 kJ/mol 2.01465035791 ± 0.00000000040 14452-69-8*0 Methyl formate HC(O)OCH3 (g) -346.88 -359.92 ± 0.84 kJ/mol 60.0520 ± 0.0017 107-31-3*0 Iodine I (g, 2P1/2) 198.109 197.709 ± 0.0021 kJ/mol 126.904470 ± 0.000030 14362-44-8*2 Hydrazine monohydrate (NH2NH2)(H2O) (l) -242.66 ± 0.19 kJ/mol 50.06052 ± 0.00053 7803-57-8*500 Hydrogen peroxide cation [H2O2]+ (g, trans, ortho) 897.23 890.25 ± 0.51 kJ/mol 34.01413 ± 0.00062 12325-10-9*11 Acetylene anion [HCCH]- (g) 356.8 356.7 ± 1.9 kJ/mol 26.0378 ± 0.0016 50443-89-5*0 Difluorodioxidanium [FOOF]+ (g, cis) 1287.2 1283.0 ± 2.3 kJ/mol 69.99506 ± 0.00060 *7783-44-0*2 1-Propenylium [CH3CHCH]+ (g, trans) 1233.8 1223.4 ± 2.0 kJ/mol 41.0713 ± 0.0024 50457-58-4*1 Ethyl formate HC(O)OCH2CH3 (g) -375.2 -393.9 ± 1.2 kJ/mol 74.0785 ± 0.0025 109-94-4*0 1,3-Butadiyn-4-ylium-1-yl [CCCC]+ (g) 2109.9 2120.5 ± 2.9 kJ/mol 48.0423 ± 0.0032 124708-46-9*0 Acetylene HCCH (g, cis-triplet) 599.0 598.9 ± 1.5 kJ/mol 26.0373 ± 0.0016 74-86-2*11 Trihydrogen cation [H3]+ (g, para) 1110.304 1106.697 ± 0.013 kJ/mol 3.02327 ± 0.00021 28132-48-1*2 1,3-Butadiynyl anion [CCCC]- (g) 677.7 686.8 ± 1.2 kJ/mol 48.0433 ± 0.0032 59158-53-1*0 1-Propenylide [CH3CHCH]- (g, trans) 210.5 199.4 ± 2.1 kJ/mol 41.0723 ± 0.0024 65887-20-9*1 Oxoniumyl ion [H2O]+ (g, ortho) 978.467 975.563 ± 0.028 kJ/mol 18.01473 ± 0.00033 56583-62-1*1 Bromodioxy BrOO (g) 118.2 109.1 ± 4.3 kJ/mol 111.9028 ± 0.0012 67177-47-3*0 2-Hydroxyethylium [CH2CH2OH]+ (g, gauche) 1024.5 1011.9 ± 2.0 kJ/mol 45.0600 ± 0.0017 38607-31-7*1 Hydroxyoxoammoniumyl [HONO]+ (g, cis) 1014.8 1008.4 ± 2.0 kJ/mol 47.01293 ± 0.00061 80371-48-8*2 sec-Butylium [CH3CH2CHCH3]+ (g) 792.9 769.3 ± 1.7 kJ/mol 57.1137 ± 0.0033 16548-59-7*0 Hydrogen fluoride HF (aq, 45 H2O) -321.15 ± 0.16 kJ/mol 20.006343 ± 0.000070 7664-39-3*906 Trioxodinitrate anion [ONN(O)O]- (g, non-vdW) -87.3 -93.1 ± 2.2 kJ/mol 76.01223 ± 0.00091 194856-62-7*1 Chlorine atom Cl (g, 2P3/2) 119.621 121.228 ± 0.0011 kJ/mol 35.45270 ± 0.00090 22537-15-1*1 Tribromine cation [Br3]+ (g) 1035.9 1013.2 ± 2.6 kJ/mol 239.7115 ± 0.0030 33105-86-1*0 Hydroxymethylene HCOH (g) 112.67 108.91 ± 0.27 kJ/mol 30.02598 ± 0.00087 19710-56-6*0 Succinic acid (CH2C(O)OH)2 (cr,l) -918.55 -940.28 ± 0.13 kJ/mol 118.0880 ± 0.0034 110-15-6*500 Hydroxylamine NH2OH (g) -33.12 -43.49 ± 0.45 kJ/mol 33.02996 ± 0.00037 7803-49-8*0 1,2-Dibromoethane CH2BrCH2Br (cr,l) -80.2 ± 1.2 kJ/mol 187.8612 ± 0.0026 106-93-4*500 1,3-Butadien-2-ol CH2C(OH)CHCH2 (g, s-cis, syn) -43.2 -59.7 ± 2.3 kJ/mol 70.0898 ± 0.0032 59120-04-6*21 1,3-Butadien-2-ol CH2C(OH)CHCH2 (g, s-trans) -53.9 -69.1 ± 1.6 kJ/mol 70.0898 ± 0.0032 59120-04-6*1 Deuterium molecule cation [D2]+ (g) 1492.286 1492.361 ± 0.000 kJ/mol 4.02765497609 ± 0.00000000080 12184-84-8*0 Acrolein CH2CHCHO (g) -55.3 -65.4 ± 1.2 kJ/mol 56.0633 ± 0.0024 107-02-8*0 1,2-Propadien-1-one cation [CH2CCO]+ (g) 1012.6 1011.2 ± 1.9 kJ/mol 54.0468 ± 0.0024 87612-93-9*0 Nitrosyl nitrite anion [ONONO]- (g, t, c) -100.3 -103.5 ± 2.9 kJ/mol 76.01223 ± 0.00091 *122413-35-8*2 2-Propynal cation [CHCCHO]+ (g) 1168.3 1167.2 ± 1.6 kJ/mol 54.0468 ± 0.0024 100815-70-1*0 mu-Oxodichlorate anion [ClOCl]- (g) -147.8 -147.7 ± 2.5 kJ/mol 86.9053 ± 0.0018 365546-30-1*0 Acetoxy CH3C(O)O (g, 2A") -182.8 -191.6 ± 1.2 kJ/mol 59.0440 ± 0.0017 13799-69-4*1 Isocyanogen bromide anion [BrNC]- (g) 105.3 102.1 ± 4.6 kJ/mol 105.9220 ± 0.0013 *238754-53-5*0 Peroxyhypochlorous acid cation [HOOCl]+ (g, cis) 1050.8 1045.1 ± 2.5 kJ/mol 68.4589 ± 0.0011 *67952-07-2*2 Diatomic bromine cation [Br2]+ (g) 1060.32 1045.37 ± 0.23 kJ/mol 159.8075 ± 0.0020 12595-71-0*0 Hydrogen peroxide cation [H2O2]+ (g, cis, para) 930.98 924.12 ± 0.98 kJ/mol 34.01413 ± 0.00062 12325-10-9*22 Nitrous acid anion [HONO]- (g, trans) -105.5 -109.4 ± 1.8 kJ/mol 47.01403 ± 0.00061 256393-36-9*1 Bicyclo[1.1.0]buta-1,3-dien-4-ylium-2-yl [C(CC)C]+ (g) 2087.4 2097.2 ± 2.7 kJ/mol 48.0423 ± 0.0032 289679-91-0*0 Tribromide [Br3]- (aq) -129.23 ± 0.26 kJ/mol 239.7125 ± 0.0030 14522-80-6*800 2-Chloro ozone ClO(O)O (g) 265.9 265.3 ± 3.7 kJ/mol 83.4509 ± 0.0013 *141801-66-3*0 Cyanoacetylene cation [HCCCN]+ (g) 1495.33 1497.63 ± 0.64 kJ/mol 51.0462 ± 0.0024 85398-68-1*0 Isocyanoacetylene cation [HCCNC]+ (g) 1567.5 1570.1 ± 1.3 kJ/mol 51.0462 ± 0.0024 145076-03-5*0 Hydrazoic acid anion [HNNN]- (g, cis) 316.2 310.0 ± 2.3 kJ/mol 43.02871 ± 0.00022 203264-98-6*2 Cyanoethynylium [CCCN]+ (g) 1867.6 1874.3 ± 3.2 kJ/mol 50.0383 ± 0.0024 104233-69-4*0 Water H2O (cr) -286.302 -292.742 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*510 Hydrazoic acid HNNN (aq, undissoc) 257.64 ± 0.48 kJ/mol 43.02816 ± 0.00022 7782-79-8*1000 Acetoxy CH3C(O)O (g) -182.8 -191.5 ± 1.2 kJ/mol 59.0440 ± 0.0017 13799-69-4*0 Hydrazoic acid HNNN (aq) 272.63 ± 0.48 kJ/mol 43.02816 ± 0.00022 7782-79-8*800 Bicyclo[1.1.0]buta-1,3-dien-2-yl anion [C(CC)C]- (g) 803.7 811.3 ± 2.1 kJ/mol 48.0433 ± 0.0032 289679-89-6*0 3-Imino-2-propen-1-ylidene CHCHCNH (g, singlet) 530.6 526.3 ± 1.2 kJ/mol 53.0627 ± 0.0024 916765-05-4*1 2-(Methylidyneamino)ethenyl CHCHNCH (g, singlet) 600.6 596.3 ± 1.2 kJ/mol 53.0627 ± 0.0024 123416-74-0*1 Oxygen atom dication [O]+2 (g) 4949.459 4953.000 ± 0.013 kJ/mol 15.99830 ± 0.00030 14127-63-0*0 Oxygen atom tetracation [O]+4 (g) 17719.207 17721.064 ± 0.025 kJ/mol 15.99721 ± 0.00030 14127-65-2*0 Water trimer (H2O)3 (g) -762.73 -776.83 ± 0.21 kJ/mol 54.04584 ± 0.00099 31014-12-7*0 Peroxyhypochlorous acid anion [HOOCl]- (g, trans quartet) -2.9 -3.3 ± 2.6 kJ/mol 68.4600 ± 0.0011 *67952-08-3*1 Carbon monoxide CO (g, singlet) -113.803 -110.523 ± 0.026 kJ/mol 28.01010 ± 0.00085 630-08-0*2 Hydrogen iodide HI (aq) -56.824 ± 0.090 kJ/mol 127.912410 ± 0.000076 10034-85-2*800 Dioxaziridine HN(OO) (g) 277.5 270.8 ± 1.9 kJ/mol 47.01348 ± 0.00061 67394-35-8*0 Tetraoxygen O4 (g, D2h singlet) 69.8 65.1 ± 4.4 kJ/mol 63.9976 ± 0.0012 12596-83-7*21 Hydroxylamine NH2OH (cr,l) -107.51 ± 0.62 kJ/mol 33.02996 ± 0.00037 7803-49-8*500 Tetraoxygen O4 (g, D2d singlet) 399.0 393.2 ± 3.9 kJ/mol 63.9976 ± 0.0012 12596-83-7*23 Tetraoxygen O4 (g, D3h singlet) 465.6 459.6 ± 4.2 kJ/mol 63.9976 ± 0.0012 12596-83-7*24 Dioxofluorine cation [OFO]+ (g) 1667.0 1664.8 ± 2.8 kJ/mol 50.99665 ± 0.00060 223566-05-0*0 Methylaminyliumyl [CH3N]+ (g, doublet ?) 1388.3 1381.9 ± 2.3 kJ/mol 29.04071 ± 0.00083 56924-51-7*1 Acetaldehyde CH3CHO (cr,l) -187.06 -191.78 ± 0.31 kJ/mol 44.0526 ± 0.0017 75-07-0*500 Ethynylene C2 (g, singlet) 820.33 826.90 ± 0.26 kJ/mol 24.0214 ± 0.0016 12070-15-4*2 Oxygen atom pentacation [O]+5 (g) 28708.788 28710.646 ± 0.053 kJ/mol 15.99666 ± 0.00030 14127-66-3*0 Formylimidogen HC(O)N (g, singlet) 245.3 242.1 ± 3.3 kJ/mol 43.02478 ± 0.00086 42288-92-6*2 Disilicon Si2 (g) 581.4 585.3 ± 1.6 kJ/mol 56.17100 ± 0.00060 12597-35-2*0 Cyclopentadiene CH2(CHCHCHCH) (l) 109.89 ± 0.57 kJ/mol 66.1011 ± 0.0040 542-92-7*590 Fluorosyl fluoride FFO (g, singlet) 227. 225. ± 21. kJ/mol 53.99621 ± 0.00030 86825-57-2*2 Trihydrogen H(HH) (g, 2s 2A1' Ry) 745.878 743.094 ± 0.062 kJ/mol 3.02382 ± 0.00021 12184-91-7*1 Dioxofluorine anion [OFO]- (g) 155.9 154.3 ± 2.5 kJ/mol 50.99775 ± 0.00060 *175861-93-5*0 2-Propen-1-ylium-1-ylidene [CH2CHC]+ (g) 1373.1 1369.5 ± 2.0 kJ/mol 39.0554 ± 0.0024 88000-25-3*0 Quartz SiO2 (g) -320.4 -321.7 ± 2.4 kJ/mol 60.08430 ± 0.00067 14808-60-7*0 Formylimidogen HC(O)N (g, triplet) 245.2 242.1 ± 4.6 kJ/mol 43.02478 ± 0.00086 42288-92-6*1 Dinitrogen anion [N2]- (g) 192.5 192.5 ± 1.7 kJ/mol 28.01403 ± 0.00014 12185-02-3*0 Peroxyformyl HC(O)OO (g) -100.58 -105.69 ± 0.92 kJ/mol 61.0168 ± 0.0012 56240-83-6*0 Methanediol CH2(OH)2 (g) -379.41 -392.81 ± 0.92 kJ/mol 48.0413 ± 0.0010 463-57-0*0 2-Hydroxyethyl CH2CH2OH (g) -13.35 -26.62 ± 0.56 kJ/mol 45.0605 ± 0.0017 4422-54-2*0 Peroxyformate [HC(O)OO]- (g) -341.14 -346.59 ± 0.95 kJ/mol 61.0174 ± 0.0012 104960-05-6*0 Diiodine cation [I2]+ (g) 963.523 960.408 ± 0.018 kJ/mol 253.808391 ± 0.000060 28712-14-3*0 Isocyanomethane CH3NC (cr,l) 146.1 ± 2.2 kJ/mol 41.0520 ± 0.0016 593-75-9*500 Trihydrogen H(HH) (g, TS) 477.4 474.7 ± 2.3 kJ/mol 3.02382 ± 0.00021 12184-91-7*201 Cyanogen NCCN (cr,l) 273.93 289.18 ± 0.42 kJ/mol 52.0349 ± 0.0016 460-19-5*500 Methane anion [CH4]- (g) 27.3 19.4 ± 5.1 kJ/mol 16.04301 ± 0.00085 27680-53-1*0 Fluorosyl fluoride cation [FFO]+ (g) 1413.0 1413.4 ± 3.5 kJ/mol 53.99566 ± 0.00030 *86825-50-5*0 Cyclopropylidene C(CH2CH2) (g) 474.89 466.87 ± 0.85 kJ/mol 40.0639 ± 0.0024 2143-70-6*0 Fluoromethane cation [CH3F]+ (g) 981.81 974.31 ± 0.62 kJ/mol 34.03237 ± 0.00083 59122-96-2*0 Isocyanogen anion [CNCN]- (g) 385.5 387.6 ± 3.4 kJ/mol 52.0354 ± 0.0016 *83951-85-3*0 O--HH Complex (H2)(O) (g, vdW C2v ?) 247.2 248.2 ± 2.0 kJ/mol 18.01528 ± 0.00033 *7732-18-5*102 Ethynol cation [HCCOH]+ (g) 1063.8 1061.2 ± 2.9 kJ/mol 42.0361 ± 0.0016 84005-02-7*0 Oxonium [H3O]+ (g, ortho) 605.91 599.10 ± 0.17 kJ/mol 19.02267 ± 0.00037 13968-08-6*1 Diazene anion [HNNH]- (g, trans-cis-iso equilib) 265.5 258.7 ± 2.0 kJ/mol 30.02991 ± 0.00020 100429-75-2*0 Ethynol anion [HCCOH]- (g) 163.5 165.0 ± 3.3 kJ/mol 42.0372 ± 0.0016 864971-50-6*0 Diisocyanogen anion [CNNC]- (g) 456.3 461.9 ± 3.7 kJ/mol 52.0354 ± 0.0016 *78800-22-3*0 Water H2O (cr, l, eq.press.) -286.303 -285.831 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*499 Diisocyanogen cation [CNNC]+ (g) 1824.8 1827.9 ± 3.3 kJ/mol 52.0343 ± 0.0016 *78800-21-2*0 Diazene HNNH (g, trans-cis equilib) 207.09 199.95 ± 0.41 kJ/mol 30.02936 ± 0.00020 3618-05-1*1 Iminomethyl anion [HCNH]- (g) 237.3 233.6 ± 1.8 kJ/mol 28.03387 ± 0.00082 90623-30-6*0 Trioxidaniumyl [HOOOH]+ (g) 925.5 916.6 ± 1.5 kJ/mol 50.01353 ± 0.00091 161321-37-5*0 Ethynol HCCOH (g) 95.29 92.81 ± 0.80 kJ/mol 42.0367 ± 0.0016 32038-79-2*0 Peroxychlorous acid HOOClO (g) 96.2 90.6 ± 2.1 kJ/mol 84.4588 ± 0.0013 177778-92-6*0 2-Cyclopropyn-1-ylidene C(CC) (g) 898.9 905.8 ± 1.6 kJ/mol 36.0321 ± 0.0024 102508-15-6*0 Diazoethenylidene cation [NNCC]+ (g) 1771.2 1773.2 ± 3.5 kJ/mol 52.0343 ± 0.0016 *130760-10-0*0 Cyclopentadienide [CH(CHCHCHCH)]- (g) 100.1 87.1 ± 1.1 kJ/mol 65.0937 ± 0.0040 12127-83-2*0 Diazoethenylidene anion [NNCC]- (g) 529.7 532.3 ± 3.5 kJ/mol 52.0354 ± 0.0016 *130760-11-1*0 Cyanomethylium [CH2CN]+ (g) 1256.77 1254.13 ± 0.74 kJ/mol 40.0435 ± 0.0016 34430-18-7*0 3H-diazirin-3-ylidene-methylene CC(NN) (g) 837.3 839.9 ± 2.3 kJ/mol 52.0349 ± 0.0016 204253-88-3*0 1-Methoxyethenol CH2C(OH)OCH3 (g) -284.9 -303.4 ± 1.7 kJ/mol 74.0785 ± 0.0025 4453-91-2*0 trans-Cycloheptene CH2(CHCHCH2CH2CH2CH2 (g) 141.6 103.5 ± 1.9 kJ/mol 96.1702 ± 0.0057 45509-99-7*0 Propylidene anion [CH3CH2CH]- (g) 300.8 286.6 ± 3.2 kJ/mol 42.0803 ± 0.0024 *121408-55-7*0 Hydrazine anion [NH2NH2]- (g) 232.2 217.8 ± 4.1 kJ/mol 32.04579 ± 0.00031 65391-88-0*0 Oxiranylium [CH2(CHO)]+ (g) 901.1 893.2 ± 1.5 kJ/mol 43.0441 ± 0.0016 57789-76-1*0 Diazene anion [HNNH]- (g, trans-cis equilib) 265.5 258.7 ± 2.0 kJ/mol 30.02991 ± 0.00020 100429-75-2*1 Isocyanogen chloride cation [ClNC]+ (g) 1480.8 1482.1 ± 3.9 kJ/mol 61.4696 ± 0.0012 956475-91-5*0 Ethynol HCCOH (g, t-c triplet) 406.4 403.2 ± 3.2 kJ/mol 42.0367 ± 0.0016 32038-79-2*12 Oxiranyl anion [CH2(CHO)]- (g) 121.2 113.3 ± 1.5 kJ/mol 43.0452 ± 0.0016 72722-59-9*0 Difluorodioxidane anion [FOOF]- (g) -251. -251. ± 28. kJ/mol 69.99615 ± 0.00060 *7783-45-1*0 Ethynol HCCOH (g, t-t triplet) 409.4 406.3 ± 3.2 kJ/mol 42.0367 ± 0.0016 32038-79-2*13 Nitrogen atom N (g, doublet) 700.555 702.458 ± 0.024 kJ/mol 14.006740 ± 0.000070 17778-88-0*2 Water H2O (cr, eq.press.) -286.303 -292.744 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*509 Formic acid cation [HC(O)OH]+ (g) 721.87 715.34 ± 0.26 kJ/mol 46.0248 ± 0.0010 50614-05-6*0 Phenol cation [C6H5OH]+ (g) 746.05 727.25 ± 0.64 kJ/mol 94.1107 ± 0.0048 40932-22-7*0 Phenol anion [C6H5OH]- (g) 22.7 7.7 ± 4.9 kJ/mol 94.1118 ± 0.0048 38752-11-3*0 Ethynol HCCOH (g, c-t triplet) 455.5 452.2 ± 3.2 kJ/mol 42.0367 ± 0.0016 32038-79-2*14 Formic acid anion [HC(O)OH]- (g) -256.2 -262.3 ± 1.8 kJ/mol 46.0259 ± 0.0010 19066-82-1*0 Nitrogen atom anion N- (g) 487.6 489.9 ± 2.5 kJ/mol 14.007289 ± 0.000070 17778-87-9*0 Fluoromethane CH3F (l) -245.75 ± 0.45 kJ/mol 34.03292 ± 0.00083 593-53-3*590 Cyanic fluoride cation [FCN]+ (g) 1294.4 1294.9 ± 1.1 kJ/mol 45.01529 ± 0.00080 62532-69-8*0 Nitrato [ON(O)O]+ (g) 1290.61 1285.90 ± 0.86 kJ/mol 62.00439 ± 0.00090 133057-96-2*0 Benzaldehyde cation [C6H5C(O)H]+ (g) 896.8 880.1 ± 1.9 kJ/mol 106.1214 ± 0.0056 80226-59-1*0 Benzaldehyde anion [C6H5C(O)H]- (g) -60.2 -77.8 ± 1.2 kJ/mol 106.1225 ± 0.0056 34473-57-9*0 1-Propen-1-yl-3-ylidene CHCHCH (g) 656.6 653.2 ± 1.1 kJ/mol 39.0559 ± 0.0024 84654-90-0*0 2-Propenylidene CHCHCH2 (g, triplet) 417.4 410.5 ± 1.5 kJ/mol 40.0639 ± 0.0024 19527-08-3*1 Ethynol HCCOH (g, c-c triplet) 464.1 460.9 ± 3.2 kJ/mol 42.0367 ± 0.0016 32038-79-2*15 C=O-C cation [COC]+ (g) 1585.8 1592.9 ± 2.7 kJ/mol 40.0203 ± 0.0016 83483-98-1*0 Hydrogen peroxide H2O2 (aq) -190.76 ± 0.30 kJ/mol 34.01468 ± 0.00062 7722-84-1*800 Bromine atom Br (g, 2P1/2) 162.001 155.939 ± 0.056 kJ/mol 79.90400 ± 0.00100 10097-32-2*2 Nitrosyl nitrate ONONO2 (g) 48.3 40.4 ± 1.8 kJ/mol 92.0111 ± 0.0012 15969-55-8*0 Tetraoxidanyl HOOOO (g) 2.0 0.2 ± 3.0 kJ/mol 65.0055 ± 0.0012 69696-93-1*0 2-Propenylidene CHCHCH2 (g) 417.4 410.5 ± 1.5 kJ/mol 40.0639 ± 0.0024 19527-08-3*0 Chloromethane CH3Cl (l) -106.11 -102.15 ± 0.25 kJ/mol 50.4872 ± 0.0012 74-87-3*590 Hydroperoxonium [H2OOH]+ (g) 738.1 727.8 ± 1.2 kJ/mol 35.02207 ± 0.00064 70850-26-9*0 Cyanic fluoride anion [FCN]- (g) -20.4 -18.4 ± 2.9 kJ/mol 45.01639 ± 0.00080 34507-50-1*0 Methyl bromide cation [CH3Br]+ (g) 996.84 981.93 ± 0.27 kJ/mol 94.9380 ± 0.0013 12538-70-4*0 1-Propen-1-yl-3-ylidene CHCHCH (g, c-t quartet) 656.6 653.1 ± 2.0 kJ/mol 39.0559 ± 0.0024 84654-90-0*12 Oxoniumyl ion [H2O]+ (g, para) 978.716 975.565 ± 0.028 kJ/mol 18.01473 ± 0.00033 56583-62-1*2 Trihydrogen cation [H3]+ (g, ortho) 1110.577 1106.695 ± 0.013 kJ/mol 3.02327 ± 0.00021 28132-48-1*1 Hydroperoxonium [H2OOH]+ (g, cis) 762.5 752.7 ± 2.0 kJ/mol 35.02207 ± 0.00064 70850-26-9*2 Water anion [H2O]- (g) -50.1 -53.0 ± 4.3 kJ/mol 18.01583 ± 0.00033 12259-30-2*0 Aminomethylidyne anion [CNH2]- (g, triplet) 481.6 478.0 ± 3.2 kJ/mol 28.03387 ± 0.00082 96808-04-7*1 Dioxohydrazine ONNO (g, trans) 192.2 188.7 ± 1.8 kJ/mol 60.01228 ± 0.00062 16824-89-8*1 1-Propen-1-yl-3-ylidene CHCHCH (g, t-t quartet) 665.7 662.2 ± 2.0 kJ/mol 39.0559 ± 0.0024 84654-90-0*13 Hydrogen peroxide cation [H2O2]+ (g, trans, para) 897.25 890.25 ± 0.51 kJ/mol 34.01413 ± 0.00062 12325-10-9*12 Nitrogen sesquioxide cation [ONN(O)O]+ (g, vdW) 1027.6 1023.7 ± 4.8 kJ/mol 76.01113 ± 0.00091 *10544-73-7*0 Hydrogen isocyanide anion [HNC]- (g) 191.50 191.68 ± 0.33 kJ/mol 27.02593 ± 0.00081 96913-22-3*0 1-Propen-1-yl-3-ylidene CHCHCH (g, doublet) 699.2 696.3 ± 3.4 kJ/mol 39.0559 ± 0.0024 84654-90-0*2 Ethylidene CH3CH (g) 361.20 354.22 ± 0.51 kJ/mol 28.0532 ± 0.0016 4218-50-2*0 Hydroxyformyl HOCO (g) -181.13 -183.67 ± 0.44 kJ/mol 45.0174 ± 0.0010 2564-86-5*0 Iodine monochloride ICl (cr,l) -36.511 -35.537 ± 0.063 kJ/mol 162.35717 ± 0.00090 7790-99-0*500 Acetone enol CH3C(OH)CH2 (g) -152.0 -168.9 ± 1.1 kJ/mol 58.0791 ± 0.0025 29456-04-0*0 Diazenide [NNH]- (g) 175.6 176.7 ± 1.6 kJ/mol 29.02197 ± 0.00016 71004-29-0*0 Peroxyhypochlorous acid cation [HOOCl]+ (g) 1030.3 1024.5 ± 2.5 kJ/mol 68.4589 ± 0.0011 *67952-07-2*0 Dinitrogen tetraoxide O2NNO2 (cr,l) -37.86 -27.01 ± 0.19 kJ/mol 92.0111 ± 0.0012 10544-72-6*500 Hydroxyformyl anion [HOCO]- (g) -319.52 -321.38 ± 0.58 kJ/mol 45.0180 ± 0.0010 78944-70-4*0 Methyl iodide cation [CH3I]+ (g) 944.80 935.40 ± 0.18 kJ/mol 141.93844 ± 0.00083 12538-72-6*0 Isocyanogen chloride anion [ClNC]- (g) 102.8 107.2 ± 3.9 kJ/mol 61.4707 ± 0.0012 923019-39-0*0 Fluorine atom F (g, 2P1/2) 82.096 83.881 ± 0.048 kJ/mol 18.99840320 ± 0.00000050 14762-94-8*2 2-Hydroxyethenyl CHCHOH (g) 138.01 132.19 ± 0.92 kJ/mol 43.0446 ± 0.0016 108665-16-3*0 Nitrosodioxaziridine ONN(OO) (g, gauche) 415.3 409.5 ± 2.8 kJ/mol 76.01168 ± 0.00091 132871-99-9*3 Methyl nitrite CH3ONO (g, trans) -52.56 -64.52 ± 0.90 kJ/mol 61.0401 ± 0.0010 624-91-9*1 Methyl nitrite CH3ONO (cr,l) -88.91 ± 0.56 kJ/mol 61.0401 ± 0.0010 624-91-9*500 1,2-Dibromoethene CHBrCHBr (g) 121.1 100.9 ± 2.1 kJ/mol 185.8453 ± 0.0026 540-49-8*0 Fluoroform CHF3 (l) -704.45 ± 0.43 kJ/mol 70.01385 ± 0.00080 75-46-7*590 Chlorine atom Cl (g, 2P1/2) 130.176 131.783 ± 0.0011 kJ/mol 35.45270 ± 0.00090 22537-15-1*2 Vinyl alcohol cation [CH2CHOH]+ (g) 778.7 767.7 ± 1.3 kJ/mol 44.0520 ± 0.0017 57239-63-1*0 Trihydrogen H(HH) (g, Ry) 745.878 743.199 ± 0.062 kJ/mol 3.02382 ± 0.00021 12184-91-7*0 2,2,4-Trimethylpentane (CH3)2CHCH2C(CH3)3 (g) -171.3 -223.7 ± 1.5 kJ/mol 114.2285 ± 0.0065 540-84-1*0 Dioxoethylium [OCHCO]+ (g) 688.1 689.4 ± 3.1 kJ/mol 57.0276 ± 0.0017 *1994332-01-2*0 Dichlorovinylidene CCCl2 (g) 421.6 424.9 ± 3.0 kJ/mol 94.9268 ± 0.0024 20394-25-6*0 Dioxohydrazine ONNO (g) 172.89 171.13 ± 0.14 kJ/mol 60.01228 ± 0.00062 16824-89-8*0 Hydroperoxyimidogen HOON (g, cis) 111.8 108.9 ± 2.8 kJ/mol 47.01348 ± 0.00061 877456-58-1*2 Chlorovinylidene CCHCl (g) 428.0 429.7 ± 3.0 kJ/mol 60.4820 ± 0.0018 70277-82-6*0 Carbonylmethyloxonium [CH3OCO]+ (g) 561.4 553.2 ± 3.2 kJ/mol 59.0435 ± 0.0017 24434-00-2*0 Carbon atom C (diamond) 2.391 1.863 ± 0.044 kJ/mol 12.01070 ± 0.00080 7440-44-0*501 Perchloric acid cation [HOCl(O)(O)O]+ (g) 1191.8 1182.2 ± 3.5 kJ/mol 100.4577 ± 0.0015 91712-47-9*0 Trioxodinitrate anion [ONN(O)O]- (g) -104.3 -107.5 ± 1.9 kJ/mol 76.01223 ± 0.00091 194856-62-7*0 Hydroxymethylene cation [HCOH]+ (g) 971.9 968.3 ± 1.4 kJ/mol 30.02543 ± 0.00087 135395-06-1*0 1,2-Difluoroethene CHFCHF (g) -302.90 -308.99 ± 0.90 kJ/mol 64.0341 ± 0.0016 1691-13-0*0 Water H2O (g, ortho) -238.647 -241.835 ± 0.026 kJ/mol 18.01528 ± 0.00033 7732-18-5*1 1,1-Dibromoethane CH3CHBr2 (cr,l) -67.2 ± 1.3 kJ/mol 187.8612 ± 0.0026 557-91-5*500 Dichloromethylene CCl2 (g) 229.51 230.69 ± 0.64 kJ/mol 82.9161 ± 0.0020 1605-72-7*0 Nitrosodioxaziridine ONN(OO) (g) 413.6 408.2 ± 1.8 kJ/mol 76.01168 ± 0.00091 132871-99-9*0 Methoxyoxomethyl CH3OCO (g) -152.5 -160.2 ± 1.5 kJ/mol 59.0440 ± 0.0017 16481-04-2*0 Oxiranylidene CH2(CO) (g) 213.5 209.2 ± 1.4 kJ/mol 42.0367 ± 0.0016 50983-85-2*0 Ethenol CH2CHOH (g) -113.12 -123.51 ± 0.52 kJ/mol 44.0526 ± 0.0017 557-75-5*0 Ethanedial anion [OCHCO]- (g) -189.2 -190.8 ± 3.3 kJ/mol 57.0287 ± 0.0017 1994332-01-2*0 Imidogen NH (g, triplet) 358.74 358.78 ± 0.16 kJ/mol 15.014680 ± 0.000099 13774-92-0*1 Difluorovinylidene anion [CCF2]- (g) -88.2 -87.1 ± 2.3 kJ/mol 62.0188 ± 0.0016 107693-92-5*0 Carbon atom C (g, quintuplet) 1114.960 1120.106 ± 0.047 kJ/mol 12.01070 ± 0.00080 7440-44-0*3 Dibromovinylidene CCBr2 (g) 510.9 499.8 ± 4.1 kJ/mol 183.8294 ± 0.0026 261771-36-2*0 Fluorovinylidene CCHF (g) 298.9 300.1 ± 3.1 kJ/mol 44.0277 ± 0.0016 70302-00-0*0 Isocyanic fluoride anion [FNC]- (g) 74.3 75.9 ± 5.7 kJ/mol 45.01639 ± 0.00080 357426-78-9*0 Krypton dication [Kr]+2 (g) 3701.124 3701.124 ± 0.013 kJ/mol 83.7989 ± 0.1000 18469-91-5*0 1,2-Propadien-1-yl-3-ylidene anion [CCC]- (g, lin) 622.0 629.4 ± 1.3 kJ/mol 36.0326 ± 0.0024 109292-47-9*1 Xenon dication [Xe]+2 (g) 3194.14 3194.14 ± 0.36 kJ/mol 131.2889 ± 0.0200 14066-95-6*0 Methoxyoxomethyl CH3OCO (g, syn-staggered) -151.8 -160.8 ± 2.2 kJ/mol 59.0440 ± 0.0017 16481-04-2*2 Diazanide [NH2NH]- (g) 249.3 239.2 ± 3.1 kJ/mol 31.03785 ± 0.00025 25415-88-7*0 Cyanogen bromide cation [BrCN]+ (g) 1331.6 1325.2 ± 1.1 kJ/mol 105.9209 ± 0.0013 34749-77-4*0 3-Buten-2-one CH3C(O)CHCH2 (g) -95.57 -111.11 ± 0.87 kJ/mol 70.0898 ± 0.0032 78-94-4*0 Dioxymethylene HCOO (g) 341.8 339.8 ± 3.0 kJ/mol 45.0174 ± 0.0010 438586-67-5*0 3-Buten-2-one CH3C(O)CHCH2 (g, cis) -94.0 -110.0 ± 1.6 kJ/mol 70.0898 ± 0.0032 78-94-4*2 Dicarbon monoxide CCO (g) 377.12 381.16 ± 0.83 kJ/mol 40.0208 ± 0.0016 12071-23-7*0 1,3-Butadien-2-ol CH2C(OH)CHCH2 (g, s-trans, anti) -48.5 -64.8 ± 2.3 kJ/mol 70.0898 ± 0.0032 59120-04-6*12 Hydroxyoxoethenylium [HOCCO]+ (g) 866.2 864.9 ± 3.5 kJ/mol 57.0276 ± 0.0017 *1994332-00-1*0 1,3-Butadien-2-ol CH2C(OH)CHCH2 (g, s-cis, anti) -38.4 -54.7 ± 2.3 kJ/mol 70.0898 ± 0.0032 59120-04-6*22 Ethynediolide [HOCCO]- (g) -133.2 -134.3 ± 3.5 kJ/mol 57.0287 ± 0.0017 1994332-00-1*0 1,3-Butadien-2-ol CH2C(OH)CHCH2 (g, s-cis) -43.2 -59.2 ± 2.3 kJ/mol 70.0898 ± 0.0032 59120-04-6*2 1,3-Butadien-2-ol CH2C(OH)CHCH2 (g) -53.9 -68.8 ± 1.6 kJ/mol 70.0898 ± 0.0032 59120-04-6*0 Cyanogen chloride cation [ClCN]+ (g) 1326.05 1327.38 ± 0.97 kJ/mol 61.4696 ± 0.0012 37612-72-9*0 Methoxyoxomethyl CH3OCO (g, anti-eclipsed) -151.6 -159.7 ± 2.2 kJ/mol 59.0440 ± 0.0017 16481-04-2*3 2-Hydroxyethylium [CH2CH2OH]+ (g) 1019.1 1007.0 ± 1.5 kJ/mol 45.0600 ± 0.0017 38607-31-7*0 Bromovinylidene CCHBr (g) 466.6 460.5 ± 3.8 kJ/mol 104.9333 ± 0.0019 161957-27-3*0 Water dimer cation [(H2O)2]+ (g) 556.8 546.4 ± 3.0 kJ/mol 36.03001 ± 0.00066 158061-35-9*0 Hydroxymethylene anion [HCOH]- (g) 147.1 144.2 ± 1.6 kJ/mol 30.02653 ± 0.00087 207914-87-2*0 Trioxygen difluoride FOOOF (g, cis) 113.4 107.6 ± 2.1 kJ/mol 85.99501 ± 0.00090 16829-28-0*2 1,2-Propadien-1-one anion [CH2CCO]- (g) 49.5 48.3 ± 3.1 kJ/mol 54.0479 ± 0.0024 159171-62-7*0 Difluorophosgene anion [CF2O]- (g) -602.3 -604.2 ± 3.3 kJ/mol 66.00745 ± 0.00085 474815-26-4*0 1,2-Dichloroethene CHClCHCl (g) 3.47 -1.85 ± 0.54 kJ/mol 96.9427 ± 0.0024 540-59-0*0 Isocyanogen bromide cation [BrNC]+ (g) 1470.2 1464.5 ± 5.9 kJ/mol 105.9209 ± 0.0013 238754-53-5*0 2-Cyclopropen-1-one cation [OC(CHCH)]+ (g) 1078.6 1075.5 ± 2.0 kJ/mol 54.0468 ± 0.0024 100815-68-7*0 Hypochloroperoxoous acid, hydroxy ester HOOOCl (g) 49.1 42.3 ± 1.9 kJ/mol 84.4588 ± 0.0013 928652-99-7*0 Oxirene O(CHCH) (g) 273.18 271.02 ± 0.92 kJ/mol 42.0367 ± 0.0016 157-18-6*0 Cyclopropane CH2(CH2CH2) (l) 41.41 35.72 ± 0.53 kJ/mol 42.0797 ± 0.0024 75-19-4*500 Cyanogen chloride anion [ClCN]- (g) 46.7 51.0 ± 3.1 kJ/mol 61.4707 ± 0.0012 12281-43-5*0 Fluoro(fluorooxy)methylene FCOF (g) -134.8 -136.0 ± 1.3 kJ/mol 66.00691 ± 0.00085 479587-30-9*0 Isourea NHC(OH)NH2 (g) -156.2 -172.8 ± 2.6 kJ/mol 60.05534 ± 0.00091 4744-36-9*0 Bromoform CHBr3 (l) 3.5 ± 1.3 kJ/mol 252.7306 ± 0.0031 75-25-2*590 mu-Oxodioxodinitrogen [ONONO]+ (g, t, t) 984.0 981.0 ± 3.2 kJ/mol 76.01113 ± 0.00091 87950-63-8*1 Carbamoyl anion [NH2CO]- (g) -81.7 -87.6 ± 3.1 kJ/mol 44.03327 ± 0.00087 78944-69-1*0 Fluorosyl fluoride FFO (g) 192.6 193.1 ± 2.3 kJ/mol 53.99621 ± 0.00030 86825-57-2*0 Fluorosyl fluoride anion [FFO]- (g) -147.2 -146.9 ± 3.0 kJ/mol 53.99675 ± 0.00030 *86825-57-2*0 Acetyloxoniumylidene [CH3C(O)O]+ (g, triplet) 891.7 883.2 ± 3.0 kJ/mol 59.0435 ± 0.0017 67057-47-0*1 Chloromethylene CHCl (g) 320.27 320.55 ± 0.89 kJ/mol 48.4713 ± 0.0012 2108-20-5*0 Nitrosyl nitrite anion [ONONO]- (g) -103.1 -106.2 ± 2.8 kJ/mol 76.01223 ± 0.00091 *122413-35-8*0 Peroxychlorous acid HOOClO (g, perp ?) 102.3 96.2 ± 3.7 kJ/mol 84.4588 ± 0.0013 177778-92-6*3 Formaldoxime CH2NOH (g) 30.7 20.1 ± 1.4 kJ/mol 45.04066 ± 0.00088 75-17-2*0 Difluoromethane CH2F2 (l) -468.73 ± 0.36 kJ/mol 52.02339 ± 0.00081 75-10-5*590 Methoxyethene CH2CHOCH3 (g) -89.2 -106.5 ± 1.1 kJ/mol 58.0791 ± 0.0025 107-25-5*0 Isocyanic fluoride cation [FNC]+ (g) 1618.4 1619.0 ± 4.0 kJ/mol 45.01529 ± 0.00080 *16992-26-0*0 Hydrogen peroxide cation [H2O2]+ (g, cis, ortho) 931.01 924.12 ± 0.98 kJ/mol 34.01413 ± 0.00062 12325-10-9*21 Phosgene cation [CCl2O]+ (g) 897.1 896.0 ± 1.7 kJ/mol 98.9150 ± 0.0020 73249-38-4*0 Methoxyethene CH2CHOCH3 (g, trans) -81.8 -98.9 ± 2.4 kJ/mol 58.0791 ± 0.0025 107-25-5*1 Phosgene CCl2O (cr, l, I+liquid) -242.74 ± 0.27 kJ/mol 98.9155 ± 0.0020 75-44-5*501 Phosgene CCl2O (cr, l, II+liquid) -255.44 -242.74 ± 0.27 kJ/mol 98.9155 ± 0.0020 75-44-5*502 Hydrazoic acid anion [HNNN]- (g) 309.0 303.2 ± 2.3 kJ/mol 43.02871 ± 0.00022 203264-98-6*0 Hydrazoic acid HNNN (cr,l) 261.49 ± 0.65 kJ/mol 43.02816 ± 0.00022 7782-79-8*500 Methylaminyliumyl [CH3N]+ (g, quartet) 1423.0 1416.1 ± 2.3 kJ/mol 29.04071 ± 0.00083 56924-51-7*2 Diazene cation [HNNH]+ (g, trans-iso-cis equilib) 1132.46 1125.80 ± 0.64 kJ/mol 30.02881 ± 0.00020 76986-17-9*0 Chloro(chlorooxy)methylene ClCOCl (g) 73.5 73.9 ± 3.6 kJ/mol 98.9155 ± 0.0020 479587-31-0*0 Oxide [O]-2 (g) 651. 653. ± 15. kJ/mol 16.00050 ± 0.00030 16833-27-5*0 Hydrogen peroxide H2O2 (g, ortho) -129.459 -135.465 ± 0.063 kJ/mol 34.01468 ± 0.00062 7722-84-1*1 Chlorous acid cation [HOClO]+ (g) 996.6 991.5 ± 3.1 kJ/mol 68.4589 ± 0.0011 *99559-66-7*0 Oxonium [H3O]+ (aq) -285.830 ± 0.026 kJ/mol 19.02267 ± 0.00037 13968-08-6*800 Chloro(chlorooxy)methylene ClCOCl (g, trans) 98. 105. ± 15. kJ/mol 98.9155 ± 0.0020 479587-31-0*1 Chlorine chlorite ClOClO (g) 168.6 166.4 ± 1.3 kJ/mol 102.9042 ± 0.0019 105206-44-8*0 Diazene cation [HNNH]+ (g, trans-cis equilib) 1132.46 1125.52 ± 0.64 kJ/mol 30.02881 ± 0.00020 76986-17-9*1 Chlorohydroxymethyl CH(Cl)OH (g) -54.8 -60.5 ± 1.1 kJ/mol 65.4787 ± 0.0012 147139-06-8*0 1-Cyanoethylidene CH3CCN (g) 437.5 433.7 ± 1.5 kJ/mol 53.0627 ± 0.0024 498544-34-6*0 Hydrobromate ion [HBr]- (g) -5.6 -12.1 ± 4.3 kJ/mol 80.9125 ± 0.0010 85532-97-4*0 Oxoiodonium [IO]+ (g) 1066.1 1064.1 ± 1.9 kJ/mol 142.90332 ± 0.00030 81182-81-2*0 O--HH Complex (H2)(O) (g, vdW Cinfv ?) 247.6 248.9 ± 2.7 kJ/mol 18.01528 ± 0.00033 *7732-18-5*101 Ethoxyethene CH2CHOCH2CH3 (g) -117.7 -136.2 ± 1.5 kJ/mol 72.1057 ± 0.0033 109-92-2*0 Chloroethane CH3CH2Cl (cr,l) -134.29 -135.91 ± 0.27 kJ/mol 64.5138 ± 0.0019 75-00-3*500 Ethoxyethene CH2CHOCH2CH3 (g, cis-perp) -111.2 -135.1 ± 2.3 kJ/mol 72.1057 ± 0.0033 109-92-2*21 Ethoxyethene CH2CHOCH2CH3 (g, trans-trans) -110.7 -132.9 ± 2.6 kJ/mol 72.1057 ± 0.0033 109-92-2*1 3-Imino-2-propen-1-ylidene CHCHCNH (g) 530.6 526.3 ± 1.2 kJ/mol 53.0627 ± 0.0024 916765-05-4*0 Oxoethylidene HCC(O)H (g) 261.1 258.3 ± 1.1 kJ/mol 42.0367 ± 0.0016 39920-84-8*0 3-Imino-2-propen-1-ylidene CHCHCNH (g, triplet) 571.8 567.0 ± 1.6 kJ/mol 53.0627 ± 0.0024 916765-05-4*2 Nitrous acid anion [HONO]- (g) -105.85 -109.32 ± 0.78 kJ/mol 47.01403 ± 0.00061 256393-36-9*0 Ethoxyethene CH2CHOCH2CH3 (g, trans-perp) -108.7 -131.9 ± 2.3 kJ/mol 72.1057 ± 0.0033 109-92-2*11 Propylidyne CH3CH2C (g) 492.4 482.7 ± 1.2 kJ/mol 41.0718 ± 0.0024 85056-54-8*0 Peroxyhypochlorous acid anion [HOOCl]- (g, quartet) -32.2 -34.0 ± 2.6 kJ/mol 68.4600 ± 0.0011 *67952-08-3*0 2-(Methylidyneamino)ethenyl CHCHNCH (g) 600.6 596.3 ± 1.2 kJ/mol 53.0627 ± 0.0024 123416-74-0*0 Chlorohydroxymethylene ClCOH (g, cis) 14.3 11.4 ± 3.2 kJ/mol 64.4707 ± 0.0012 147723-60-2*2 2-(Methylidyneamino)ethenyl CHCHNCH (g, triplet) 634.4 630.4 ± 1.6 kJ/mol 53.0627 ± 0.0024 123416-74-0*2 COC vdW (CO)(C) (g) 589.7 598.5 ± 1.5 kJ/mol 40.0208 ± 0.0016 *12071-24-8*0 Chlorohydroxymethylene ClCOH (g) 13.9 11.2 ± 2.6 kJ/mol 64.4707 ± 0.0012 147723-60-2*0 Cyanogen iodide cation [ICN]+ (g) 1271.4 1271.2 ± 1.6 kJ/mol 152.92136 ± 0.00080 34749-78-5*0 2-Oxo-1-ethylium-1-yl [HCC(O)H]+ (g, quartet) 1289.4 1286.7 ± 2.5 kJ/mol 42.0361 ± 0.0016 214464-96-7*1 Hydroxyamidogen HNOH (g) 101.36 94.53 ± 0.81 kJ/mol 32.02202 ± 0.00034 13940-32-4*0 Hydrogen cyanide anion [HCN]- (g) 129.509 129.030 ± 0.090 kJ/mol 27.02593 ± 0.00081 12334-27-9*0 Hydrogen peroxide cation [H2O2]+ (g) 897.23 890.25 ± 0.51 kJ/mol 34.01413 ± 0.00062 12325-10-9*0 (Chlorooxy)methylene HCOCl (g, trans) 155.4 155.2 ± 3.7 kJ/mol 64.4707 ± 0.0012 331419-80-8*1 (Chlorooxy)methylene HCOCl (g) 119.1 117.8 ± 2.7 kJ/mol 64.4707 ± 0.0012 331419-80-8*0 Chlorous acid anion [HOClO]- (g) -154.3 -156.2 ± 3.3 kJ/mol 68.4600 ± 0.0011 99559-66-7*0 (Methylamino)methyl anion [CH3NHCH2]- (g) 201.1 184.1 ± 3.2 kJ/mol 44.0763 ± 0.0017 *31277-25-5*0 Dichlorine cation [Cl2]+ (g) 1108.307 1108.286 ± 0.0062 kJ/mol 70.9049 ± 0.0018 12595-90-3*0 Dioxyamidogen HNOO (g, trans) 251.1 244.5 ± 2.5 kJ/mol 47.01348 ± 0.00061 71843-95-3*1 2-Cyanovinyl CHCHCN (g) 447.9 445.5 ± 1.2 kJ/mol 52.0547 ± 0.0024 189141-20-6*0 2-Cyanovinylium [CHCHCN]+ (g, triplet) 1517.2 1515.1 ± 1.8 kJ/mol 52.0542 ± 0.0024 85398-67-0*2 2-Cyanovinyl anion [CHCHCN]- (g) 263.7 261.4 ± 1.8 kJ/mol 52.0553 ± 0.0024 *85398-67-0*0 Isocyanic acid anion [HNCO]- (g) -54.3 -57.4 ± 3.0 kJ/mol 43.02533 ± 0.00086 *444010-28-0*0 1,2-Butadiene CH3CHCCH2 (cr,l) 137.58 138.64 ± 0.66 kJ/mol 54.0904 ± 0.0032 590-19-2*500 2-Isocyanovinyl CHCHNC (g) 543.1 541.7 ± 1.7 kJ/mol 52.0547 ± 0.0024 225798-14-1*0 (Formyloxy)methyl HC(O)OCH2 (g) -151.9 -160.0 ± 1.3 kJ/mol 59.0440 ± 0.0017 3122-12-1*0 Hydroxyaminylium [HNOH]+ (g) 1019.5 1012.4 ± 2.5 kJ/mol 32.02147 ± 0.00034 66097-71-0*0 Cyanomethyliumyl [HCCN]+ (g) 1506.7 1508.2 ± 2.3 kJ/mol 39.0355 ± 0.0016 34447-38-6*0 Cyanomethylene anion [HCCN]- (g) 286.6 287.1 ± 1.5 kJ/mol 39.0366 ± 0.0016 12373-24-9*0 Cyanomethylene HCCN (g) 479.9 483.3 ± 1.1 kJ/mol 39.0361 ± 0.0016 2612-62-6*0 Carboxymethyl CH2C(O)OH (g) -227.4 -237.3 ± 1.2 kJ/mol 59.0440 ± 0.0017 2887-46-9*0 Chloroformyl anion [ClCO]- (g) -356.5 -352.9 ± 3.3 kJ/mol 63.4633 ± 0.0012 41976-93-6*0 Isocyanomethyliumyl [HCNC]+ (g) 1505.9 1507.8 ± 3.3 kJ/mol 39.0355 ± 0.0016 99045-54-2*0 Isocyanomethylene anion [HCNC]- (g) 400.6 401.3 ± 2.1 kJ/mol 39.0366 ± 0.0016 144141-01-5*0 Isocyanomethylene HCNC (g) 582.3 584.6 ± 1.7 kJ/mol 39.0361 ± 0.0016 78694-65-2*0 Isoformyl anion [COH]- (g) 55.7 58.4 ± 1.8 kJ/mol 29.01859 ± 0.00086 81747-63-9*0 3-Oxo-1,2-propadien-1-ylium-1-yl [CCCO]+ (g) 1379.9 1385.2 ± 3.9 kJ/mol 52.0310 ± 0.0024 151455-13-9*0 3-Oxo-1,2-propadienylidene anion [CCCO]- (g) 224.0 229.8 ± 3.6 kJ/mol 52.0320 ± 0.0024 109292-50-4*0 Propynylidene HCCCH (g, singlet) 597.6 599.4 ± 1.3 kJ/mol 38.0480 ± 0.0024 67152-18-5*2 Oxoethylidene anion [HCC(O)H]- (g) 86.9 84.2 ± 2.1 kJ/mol 42.0372 ± 0.0016 106543-38-8*0 Ethane anion [CH3CH3]- (g) 41.8 26.5 ± 4.4 kJ/mol 30.0696 ± 0.0017 54064-82-3*0 2-Propenylidene CHCHCH2 (g, triplet syn) 419.0 411.4 ± 2.3 kJ/mol 40.0639 ± 0.0024 19527-08-3*12 Propargylenide [HCCCH]- (g) 434.4 437.6 ± 1.1 kJ/mol 38.0485 ± 0.0024 82906-05-6*0 Cyanic acid cation [HOCN]+ (g) 1135.8 1133.2 ± 2.9 kJ/mol 43.02423 ± 0.00086 59780-31-3*0 Cyanic acid anion [HOCN]- (g) -9.2 -9.5 ± 3.1 kJ/mol 43.02533 ± 0.00086 58199-47-6*0 Trihydrogen HHH (g, TS) 254.5 250.7 ± 1.2 kJ/mol 3.02382 ± 0.00021 12184-91-7*200 Ethylene anion [CH2CH2]- (g) 232.0 225.6 ± 2.0 kJ/mol 28.0537 ± 0.0016 34527-91-8*0 Cyclobutenyl anion [CH2(CHCHCH)]- (g) 318.3 305.9 ± 3.7 kJ/mol 53.0830 ± 0.0032 60211-42-9*0 Hydrodioxonitrogen cation [HN(O)O]+ (g) 1130.2 1123.6 ± 3.0 kJ/mol 47.01293 ± 0.00061 252986-76-8*0 Methylaminyliumyl [CH3N]+ (g ?) 1388.3 1381.9 ± 2.3 kJ/mol 29.04071 ± 0.00083 56924-51-7*0 2-Methoxy-2-oxoethyl CH2C(O)OCH3 (g) -203.4 -218.7 ± 1.6 kJ/mol 73.0706 ± 0.0025 54668-31-4*0 Peroxyformic acid HC(O)OOH (g) -279.38 -288.52 ± 0.88 kJ/mol 62.0248 ± 0.0012 107-32-4*0 Phenylperoxy cation [C6H5OO]+ (g) 1018.0 1001.0 ± 3.1 kJ/mol 109.1022 ± 0.0049 956036-17-2*0 Phenylperoxy anion [C6H5OO]- (g) -39.8 -56.8 ± 3.3 kJ/mol 109.1032 ± 0.0049 *956036-17-2*0 Oxirene O(CHCH) (g, triplet) 387.8 384.5 ± 1.4 kJ/mol 42.0367 ± 0.0016 157-18-6*1 Hydrodioxonitrate [HN(O)O]- (g) -61.8 -68.2 ± 3.2 kJ/mol 47.01403 ± 0.00061 61508-71-2*0 2-Iodoethanol ICH2CH2OH (g) -132.0 -150.2 ± 2.5 kJ/mol 171.9650 ± 0.0017 624-76-0*0 Pentachloroethylium [CCl3CCl2]+ (g) 836.2 834.5 ± 3.3 kJ/mol 201.2844 ± 0.0048 *7094-17-9*0 Nitrosodioxaziridine ONN(OO) (g, cis) 413.9 408.1 ± 3.2 kJ/mol 76.01168 ± 0.00091 132871-99-9*2 Fulvene cation [CH2C(CHCHCHCH)]+ (g) 1042.9 1027.2 ± 2.8 kJ/mol 78.1113 ± 0.0048 34504-75-1*0 Fulvene anion [CH2C(CHCHCHCH)]- (g) 190.7 175.7 ± 4.1 kJ/mol 78.1124 ± 0.0048 34504-63-7*0 Dioxodiazoxane ONONO (g) 93.0 88.1 ± 1.3 kJ/mol 76.01168 ± 0.00091 122413-35-8*0 Isofulminic acid cation [HONC]+ (g) 1377.0 1374.9 ± 2.9 kJ/mol 43.02423 ± 0.00086 117800-60-9*0 Chlorine pentafluoride anion [FCl(F)(F)(F)F]- (g) -619.3 -622.7 ± 4.4 kJ/mol 130.44526 ± 0.00090 184851-42-1*0 Diazene HNNH (g, trans-cis-iso equilib) 207.09 199.95 ± 0.41 kJ/mol 30.02936 ± 0.00020 3618-05-1*0 Silicon cation Si+ (g) 1232.75 1236.88 ± 0.20 kJ/mol 28.08495 ± 0.00030 14067-07-3*0 Silicon anion Si- (g) 312.17 315.15 ± 0.20 kJ/mol 28.08605 ± 0.00030 14337-02-1*0 Difluorodioxidanium [FOOF]+ (g) 1283.6 1280.0 ± 2.3 kJ/mol 69.99506 ± 0.00060 *7783-44-0*0 Pentachloroethanide [CCl3CCl2]- (g) -283.7 -282.2 ± 3.9 kJ/mol 201.2854 ± 0.0048 263019-83-6*0 Iminomethyl HCNH (g) 275.79 272.18 ± 0.61 kJ/mol 28.03332 ± 0.00082 15691-95-9*0 Tetraoxidanyl HOOOO (g, trans) 76.7 69.5 ± 6.1 kJ/mol 65.0055 ± 0.0012 69696-93-1*1 Imidogen NH (g, singlet) 509.33 509.38 ± 0.18 kJ/mol 15.014680 ± 0.000099 13774-92-0*2 Silicon carbide SiC (cr,l) -71.0 -72.1 ± 1.4 kJ/mol 40.09620 ± 0.00085 409-21-2*500 (Dimethylamino)methyl anion [(CH3)2NCH2]- (g) 189.9 165.7 ± 3.3 kJ/mol 58.1029 ± 0.0025 125231-49-4*0 Chlorine trifluoride anion [FCl(F)F]- (g) -480.4 -481.9 ± 3.6 kJ/mol 92.44846 ± 0.00090 184289-50-7*0 (Acetyloxy)methyl CH3C(O)OCH2 (g) -200.7 -214.5 ± 1.6 kJ/mol 73.0706 ± 0.0025 2887-49-2*0 Quartz SiO2 (cr, alpha-quartz) -906.11 -911.09 ± 0.94 kJ/mol 60.08430 ± 0.00067 14808-60-7*501 Chlorine pentafluoride cation [FCl(F)(F)(F)F]+ (g) 1005.8 996.8 ± 3.3 kJ/mol 130.44417 ± 0.00090 478167-78-1*0 Quartz SiO2 (cr, alpha-tridymite) -900.8 -905.6 ± 1.6 kJ/mol 60.08430 ± 0.00067 14808-60-7*515 1-Methylethylidene CH3CCH3 (g) 315.92 303.02 ± 0.99 kJ/mol 42.0797 ± 0.0024 40852-89-9*0 Neon dication [Ne]+2 (g) 6032.988 6033.214 ± 0.0041 kJ/mol 20.17860 ± 0.00060 14041-55-5*0 Neon trication [Ne]+3 (g) 12152.403 12152.403 ± 0.033 kJ/mol 20.17805 ± 0.00060 14158-25-9*0 Neon tetracation [Ne]+4 (g) 21529.82 21531.45 ± 0.25 kJ/mol 20.17751 ± 0.00060 14041-56-6*0 Neon pentacation [Ne]+5 (g) 33711.1 33711.1 ± 1.2 kJ/mol 20.17696 ± 0.00060 14175-48-5*0 Neon hexacation [Ne]+6 (g) 48949.3 48949.3 ± 1.3 kJ/mol 20.17641 ± 0.00060 14041-57-7*0 Neon heptacation [Ne]+7 (g) 68948.7 68948.7 ± 1.5 kJ/mol 20.17586 ± 0.00060 14175-50-9*0 Neon octacation [Ne]+8 (g) 92018.2 92018.2 ± 1.5 kJ/mol 20.17531 ± 0.00060 14782-26-4*0 Neon nonacation [Ne]+9 (g) 207396.1 207396.1 ± 1.5 kJ/mol 20.17476 ± 0.00060 15721-59-2*0 Neon cation Ne+ (g) 2080.662 2080.769 ± 0.000 kJ/mol 20.17915 ± 0.00060 14782-23-1*0 Neon decacation [Ne]+10 (g) 338828.3 338828.3 ± 1.5 kJ/mol 20.17421 ± 0.00060 32218-07-8*0 Argon dimer cation [Ar2]+ (g) 1393.760 1391.173 ± 0.018 kJ/mol 79.8955 ± 0.0020 17596-58-6*0 Argon cation Ar+ (g) 1520.571 1520.580 ± 0.000 kJ/mol 39.94745 ± 0.00100 14791-69-6*0 Argon dimer Ar2 (g) -1.013 -6.347 ± 0.0051 kJ/mol 79.8960 ± 0.0020 12595-59-4*0 Helium cation He+ (g) 2372.322 2372.322 ± 0.000 kJ/mol 4.0020534 ± 0.0000020 14234-48-1*0 Helium dication [He]+2 (g) 7622.839 7622.839 ± 0.000 kJ/mol 4.0015048 ± 0.0000020 12587-46-1*0 Helium anion He- (g, 1s2.2s 2S1/2) 51. 51. ± 130. kJ/mol 4.0031506 ± 0.0000020 14452-58-5*1 Helium anion He- (g) 51. 51. ± 130. kJ/mol 4.0031506 ± 0.0000020 14452-58-5*0 Argon anion Ar- (g, 2S1/2) 23. 23. ± 75. kJ/mol 39.94855 ± 0.00100 16544-90-4*1 Argon anion Ar- (g) 23. 23. ± 75. kJ/mol 39.94855 ± 0.00100 16544-90-4*0 Helium anion He- (g, 1s.2s2 2S1/2) 1868.43 1868.43 ± 0.11 kJ/mol 4.0031506 ± 0.0000020 14452-58-5*2 Helium anion He- (g, 1s.2s.2p 4P) 1904.823 1904.824 ± 0.0011 kJ/mol 4.0031506 ± 0.0000020 14452-58-5*3 Helium anion He- (g, 2p3 4S3/2) 5724.9 5724.9 ± 1.5 kJ/mol 4.0031506 ± 0.0000020 14452-58-5*4 Argon anion Ar- (g, 4S3/2) 1111.116 1111.116 ± 0.098 kJ/mol 39.94855 ± 0.00100 16544-90-4*2 Hydron H+ (aq) 0 0 exact 1.007391 ± 0.000070 12408-02-5*800