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 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) 711.401 716.886 ± 0.050 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) 470.577 472.440 ± 0.024 kJ/mol 14.006740 ± 0.000070 17778-88-0*0 Carbon dioxide CO2 (g) -393.109 -393.475 ± 0.015 kJ/mol 44.00950 ± 0.00100 124-38-9*0 Fluorine atom F (g) 77.263 79.369 ± 0.048 kJ/mol 18.99840320 ± 0.00000050 14762-94-8*0 Methane CH4 (g) -66.550 -74.520 ± 0.057 kJ/mol 16.04246 ± 0.00085 74-82-8*0 Water H2O (cr,l) -286.300 -285.828 ± 0.027 kJ/mol 18.01528 ± 0.00033 7732-18-5*500 Water H2O (g) -238.931 -241.834 ± 0.027 kJ/mol 18.01528 ± 0.00033 7732-18-5*0 Chlorine atom Cl (g) 119.621 121.302 ± 0.0011 kJ/mol 35.45270 ± 0.00090 22537-15-1*0 Bromine atom Br (g) 117.917 111.854 ± 0.056 kJ/mol 79.90400 ± 0.00100 10097-32-2*0 Ethane C2H6 (g) -68.29 -83.91 ± 0.14 kJ/mol 30.0690 ± 0.0017 74-84-0*0 Hydron H+ (g) 1528.084 1530.047 ± 0.000 kJ/mol 1.007391 ± 0.000070 12408-02-5*0 Hydroxyl OH (g) 37.250 37.490 ± 0.027 kJ/mol 17.00734 ± 0.00031 3352-57-6*0 Ethylene C2H4 (g) 60.96 52.45 ± 0.13 kJ/mol 28.0532 ± 0.0016 74-85-1*0 Carbon monoxide CO (g) -113.803 -110.523 ± 0.026 kJ/mol 28.01010 ± 0.00085 630-08-0*0 Hydrogen chloride HCl (g) -91.989 -92.173 ± 0.0062 kJ/mol 36.46064 ± 0.00090 7647-01-0*0 Methyl CH3 (g) 149.788 146.374 ± 0.080 kJ/mol 15.03452 ± 0.00083 2229-07-4*0 Hydrogen bromide HBr (g) -27.81 -35.66 ± 0.16 kJ/mol 80.9119 ± 0.0010 10035-10-6*0 Methanol CH3OH (g) -189.83 -200.71 ± 0.16 kJ/mol 32.04186 ± 0.00090 67-56-1*0 Hydrogen fluoride HF (g) -272.668 -272.715 ± 0.049 kJ/mol 20.006343 ± 0.000070 7664-39-3*0 Iodine atom I (g) 107.157 106.757 ± 0.0021 kJ/mol 126.904470 ± 0.000030 14362-44-8*0 Formaldehyde H2CO (g) -105.349 -109.188 ± 0.099 kJ/mol 30.02598 ± 0.00087 50-00-0*0 Acetylene HCCH (g) 228.84 228.28 ± 0.14 kJ/mol 26.0373 ± 0.0016 74-86-2*0 Nitric oxide NO (g) 90.617 91.121 ± 0.065 kJ/mol 30.00614 ± 0.00031 10102-43-9*0 Ethanol CH3CH2OH (g) -216.89 -234.61 ± 0.21 kJ/mol 46.0684 ± 0.0017 64-17-5*0 Methyl chloride CH3Cl (g) -74.25 -82.18 ± 0.25 kJ/mol 50.4872 ± 0.0012 74-87-3*0 Ethyl CH3CH2 (g) 130.92 119.86 ± 0.28 kJ/mol 29.0611 ± 0.0016 2025-56-1*0 Propane CH3CH2CH3 (g) -82.75 -105.03 ± 0.19 kJ/mol 44.0956 ± 0.0025 74-98-6*0 Nitrogen dioxide ONO (g) 36.856 34.049 ± 0.065 kJ/mol 46.00554 ± 0.00060 10102-44-0*0 Ammonia NH3 (g) -38.562 -45.554 ± 0.030 kJ/mol 17.03056 ± 0.00022 7664-41-7*0 Hydrogen cyanide HCN (g) 129.662 129.277 ± 0.091 kJ/mol 27.02538 ± 0.00081 74-90-8*0 Hydrogen iodide HI (g) 28.641 26.466 ± 0.036 kJ/mol 127.912410 ± 0.000076 10034-85-2*0 Methyl fluoride CH3F (g) -227.77 -235.80 ± 0.23 kJ/mol 34.03292 ± 0.00083 593-53-3*0 Methyl bromide CH3Br (g) -20.36 -35.76 ± 0.27 kJ/mol 94.9385 ± 0.0013 74-83-9*0 Hydrogen peroxide H2O2 (g) -129.472 -135.457 ± 0.064 kJ/mol 34.01468 ± 0.00062 7722-84-1*0 Hydroxyde [OH]- (g) -139.091 -139.058 ± 0.027 kJ/mol 17.00789 ± 0.00031 14280-30-9*0 Dioxidanyl HO2 (g) 15.16 12.26 ± 0.16 kJ/mol 33.00674 ± 0.00060 3170-83-0*0 Propylene CH3CHCH2 (g) 35.00 19.99 ± 0.22 kJ/mol 42.0797 ± 0.0024 115-07-1*0 Tetrafluoromethane CF4 (g) -927.41 -933.39 ± 0.25 kJ/mol 88.00431 ± 0.00080 75-73-0*0 Fluoride F- (g) -250.901 -249.117 ± 0.048 kJ/mol 18.99895178 ± 0.00000050 16984-48-8*0 Hypochlorous acid HOCl (g) -73.867 -76.807 ± 0.028 kJ/mol 52.46004 ± 0.00095 7790-92-3*0 Acetaldehyde CH3CHO (g) -154.97 -165.45 ± 0.28 kJ/mol 44.0526 ± 0.0017 75-07-0*0 Benzene C6H6 (g) 100.62 83.11 ± 0.25 kJ/mol 78.1118 ± 0.0048 71-43-2*0 Dibromine Br2 (g) 45.68 30.89 ± 0.11 kJ/mol 159.8080 ± 0.0020 7726-95-6*0 Diiodine I2 (g) 65.497 62.417 ± 0.0041 kJ/mol 253.808940 ± 0.000060 7553-56-2*0 Methylidyne CH (g) 592.78 596.12 ± 0.11 kJ/mol 13.01864 ± 0.00080 3315-37-5*0 Formic acid HC(O)OH (g, syn) -371.12 -378.45 ± 0.22 kJ/mol 46.0254 ± 0.0010 64-18-6*1 Fluoroform CF3H (g) -688.92 -695.87 ± 0.43 kJ/mol 70.01385 ± 0.00080 75-46-7*0 Oxonium [H3O]+ (g) 605.85 599.10 ± 0.17 kJ/mol 19.02267 ± 0.00037 13968-08-6*0 Hypoflorous acid HOF (g) -84.37 -87.27 ± 0.19 kJ/mol 36.00574 ± 0.00031 14034-79-8*0 Hypobromous acid HOBr (g) -51.38 -61.85 ± 0.57 kJ/mol 96.9113 ± 0.0010 13517-11-8*0 Methyl iodide CH3I (g) 24.48 14.94 ± 0.17 kJ/mol 141.93899 ± 0.00083 74-88-4*0 Trifluoromethyl CF3 (g) -465.15 -467.94 ± 0.49 kJ/mol 69.00591 ± 0.00080 2264-21-3*0 Propyne CH3CCH (g) 192.80 185.74 ± 0.25 kJ/mol 40.0639 ± 0.0024 74-99-7*0 Methylene CH2 (g, triplet) 390.96 391.52 ± 0.12 kJ/mol 14.02658 ± 0.00081 2465-56-7*1 Methylene CH2 (g, singlet) 428.62 429.03 ± 0.13 kJ/mol 14.02658 ± 0.00081 2465-56-7*2 Vinyl C2H3 (g) 301.11 296.91 ± 0.33 kJ/mol 27.0452 ± 0.0016 2669-89-8*0 Ketene CH2CO (g) -45.45 -48.57 ± 0.13 kJ/mol 42.0367 ± 0.0016 463-51-4*0 Tetrachloromethane CCl4 (g) -94.27 -96.44 ± 0.64 kJ/mol 153.8215 ± 0.0037 56-23-5*0 Imidogen NH (g) 358.73 358.77 ± 0.17 kJ/mol 15.014680 ± 0.000099 13774-92-0*0 Allene CH2CCH2 (g) 197.34 189.86 ± 0.26 kJ/mol 40.0639 ± 0.0024 463-49-0*0 n-Butane CH3CH2CH2CH3 (g) -98.63 -125.94 ± 0.27 kJ/mol 58.1222 ± 0.0033 106-97-8*0 Difluorophosgene COF2 (g) -603.50 -606.59 ± 0.46 kJ/mol 66.00691 ± 0.00085 353-50-4*0 Bromide Br- (g) -206.620 -212.683 ± 0.056 kJ/mol 79.90455 ± 0.00100 24959-67-9*0 Oxomethylium [HCO]+ (g) 827.802 827.217 ± 0.099 kJ/mol 29.01749 ± 0.00086 17030-74-9*0 Iodide I- (g) -187.995 -188.396 ± 0.0021 kJ/mol 126.905019 ± 0.000030 20461-54-5*0 Nitric acid HNO3 (g) -124.48 -134.20 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*0 Formyl HCO (g) 41.426 41.803 ± 0.099 kJ/mol 29.01804 ± 0.00086 2597-44-6*0 Hydroxymethyl CH2OH (g) -10.25 -16.56 ± 0.33 kJ/mol 31.03392 ± 0.00088 2597-43-5*0 Chloroxyl radical ClO (g) 101.124 101.715 ± 0.035 kJ/mol 51.45210 ± 0.00095 14989-30-1*0 Methylium [CH3]+ (g) 1099.243 1095.299 ± 0.078 kJ/mol 15.03397 ± 0.00083 14531-53-4*0 Ozone OOO (g) 144.396 141.733 ± 0.039 kJ/mol 47.99820 ± 0.00090 10028-15-6*0 Cyanogen chloride ClCN (g) 135.03 135.72 ± 0.44 kJ/mol 61.4701 ± 0.0012 506-77-4*0 Phenyl C6H5 (g) 350.37 337.08 ± 0.57 kJ/mol 77.1039 ± 0.0048 2396-01-2*0 Ethylium [CH3CH2]+ (g) 915.03 902.95 ± 0.32 kJ/mol 29.0606 ± 0.0016 14936-94-8*0 Methoxide [CH3O]- (g) -122.54 -130.27 ± 0.35 kJ/mol 31.03447 ± 0.00088 3315-60-4*0 Methoxy CH3O (g) 28.90 21.53 ± 0.34 kJ/mol 31.03392 ± 0.00088 2143-68-2*0 Tetrabromomethane CBr4 (g) 131.5 101.8 ± 1.1 kJ/mol 331.6267 ± 0.0041 558-13-4*0 Oxygen atom anion O- (g) 105.868 108.097 ± 0.0021 kJ/mol 15.99995 ± 0.00030 14337-01-0*0 Nitrilomethyl CN (g) 436.73 440.01 ± 0.15 kJ/mol 26.01744 ± 0.00080 2074-87-5*0 Cyanogen fluoride FCN (g) 8.88 9.21 ± 0.68 kJ/mol 45.01584 ± 0.00080 1495-50-7*0 Chloride Cl- (g) -228.953 -227.346 ± 0.0021 kJ/mol 35.45325 ± 0.00090 16887-00-6*0 Trihydrogen cation [H3]+ (g) 1110.304 1106.696 ± 0.013 kJ/mol 3.02327 ± 0.00021 28132-48-1*0 Cyanogen bromide BrCN (g) 187.41 180.62 ± 0.73 kJ/mol 105.9214 ± 0.0013 506-68-3*0 Methylene fluoride CH2F2 (g) -443.16 -450.73 ± 0.36 kJ/mol 52.02339 ± 0.00081 75-10-5*0 2-Propynyl CH2CCH (g) 354.00 351.44 ± 0.38 kJ/mol 39.0559 ± 0.0024 2932-78-7*0 Propynylidene HCCCH (g, triplet) 543.38 546.38 ± 0.63 kJ/mol 38.0480 ± 0.0024 67152-18-5*1 Dioxymethyl CH2OO (g) 112.43 105.42 ± 0.61 kJ/mol 46.0254 ± 0.0010 56077-92-0*0 Oxygen atom cation O+ (g) 1560.786 1562.644 ± 0.0021 kJ/mol 15.99885 ± 0.00030 14581-93-2*0 Hypochlorite [ClO]- (g) -118.60 -118.33 ± 0.13 kJ/mol 51.45265 ± 0.00095 14380-61-1*0 1,2-Propadiene-1,3-diylidene CCC (g) 814.52 823.48 ± 0.54 kJ/mol 36.0321 ± 0.0024 12075-35-3*0 Allyl CH2CHCH2 (g) 179.56 167.84 ± 0.54 kJ/mol 41.0718 ± 0.0024 1981-80-2*0 1-Hydroxyethyl CH3CHOH (g, gauche-anti) -42.16 -55.59 ± 0.61 kJ/mol 45.0605 ± 0.0017 2348-46-1*1 2-Hydroxyethyl CH2CH2OH (g, gauche-syn) -12.79 -26.06 ± 0.61 kJ/mol 45.0605 ± 0.0017 4422-54-2*1 Ethyl chloride CH3CH2Cl (g) -96.76 -111.35 ± 0.20 kJ/mol 64.5138 ± 0.0019 75-00-3*0 Hydride H- (g) 143.264 145.228 ± 0.000 kJ/mol 1.008489 ± 0.000070 12184-88-2*0 Oxygen difluoride FOF (g) 26.94 24.69 ± 0.25 kJ/mol 53.99621 ± 0.00030 7783-41-7*0 Methylenimine H2CNH (g) 96.53 88.62 ± 0.63 kJ/mol 29.04126 ± 0.00083 2053-29-4*0 Methylamine CH3NH2 (g) -5.97 -21.05 ± 0.46 kJ/mol 31.05714 ± 0.00088 74-89-5*0 Nitrite [ONO]- (g) -182.69 -185.50 ± 0.45 kJ/mol 46.00609 ± 0.00060 14797-65-0*0 Nitrosyl hydride HNO (g) 109.93 106.96 ± 0.11 kJ/mol 31.01408 ± 0.00032 14332-28-6*0 Nitrous acid HONO (g, trans) -73.018 -79.162 ± 0.079 kJ/mol 47.01348 ± 0.00061 7782-77-6*1 Ethynylene C2 (g) 820.21 828.68 ± 0.27 kJ/mol 24.0214 ± 0.0016 12070-15-4*0 Ethynyl C2H (g) 563.87 567.99 ± 0.15 kJ/mol 25.0293 ± 0.0016 2122-48-7*0 Ethoxide [CH3CH2O]- (g) -164.11 -179.05 ± 0.52 kJ/mol 45.0610 ± 0.0017 16331-64-9*0 Chloroform CCl3H (g) -98.49 -103.39 ± 0.64 kJ/mol 119.3767 ± 0.0028 67-66-3*0 Methylene chloride CH2Cl2 (g) -87.85 -94.71 ± 0.59 kJ/mol 84.9320 ± 0.0020 75-09-2*0 Tetrafluoroethylene C2F4 (g) -671.52 -674.93 ± 0.57 kJ/mol 100.0150 ± 0.0016 116-14-3*0 Phenylium [C6H5]+ (g) 1148.47 1136.57 ± 0.89 kJ/mol 77.1034 ± 0.0048 17333-73-2*0 Hypoiodous acid HOI (g) -56.6 -61.3 ± 2.0 kJ/mol 143.91181 ± 0.00031 14332-21-9*0 Amidogen NH2 (g) 188.91 186.02 ± 0.12 kJ/mol 16.02262 ± 0.00016 13770-40-6*0 Methanium [CH5]+ (g) 922.07 911.83 ± 0.44 kJ/mol 17.04985 ± 0.00087 15135-49-6*0 Hydroxylamine NH2OH (g, trans) -33.12 -43.50 ± 0.49 kJ/mol 33.02996 ± 0.00037 7803-49-8*1 Oxirane O(CH2CH2) (g) -40.00 -52.54 ± 0.38 kJ/mol 44.0526 ± 0.0017 75-21-8*0 Methyl hydroperoxide CH3OOH (g) -114.90 -127.72 ± 0.74 kJ/mol 48.0413 ± 0.0010 3031-73-0*0 Hydroxyformyl HOCO (g, trans) -180.96 -183.93 ± 0.48 kJ/mol 45.0174 ± 0.0010 2564-86-5*1 Isocyanic acid HNCO (g) -115.85 -118.85 ± 0.31 kJ/mol 43.02478 ± 0.00086 75-13-8*0 Tetraiodomethane CI4 (g) 340.8 335.7 ± 1.3 kJ/mol 519.62858 ± 0.00081 507-25-5*0 Chlorotrifluoromethane CF3Cl (g) -704.97 -710.08 ± 0.72 kJ/mol 104.4586 ± 0.0012 75-72-9*0 Bromotrifluoromethane CF3Br (g) -639.45 -651.57 ± 0.50 kJ/mol 148.9099 ± 0.0013 75-63-8*0 Fluoromethylidyne CF (g) 243.11 246.71 ± 0.13 kJ/mol 31.00910 ± 0.00080 3889-75-6*0 Fluoroxyl radical FO (g) 110.26 110.88 ± 0.15 kJ/mol 34.99780 ± 0.00030 12061-70-0*0 Dioxygen cation [O2]+ (g) 1164.585 1165.221 ± 0.0092 kJ/mol 31.99825 ± 0.00060 12185-07-8*0 Methylidyne CH (g, quartet) 664.55 667.88 ± 0.59 kJ/mol 13.01864 ± 0.00080 3315-37-5*2 Ethoxy CH3CH2O (g, X 2A") 1.16 -12.74 ± 0.51 kJ/mol 45.0605 ± 0.0017 2154-50-9*51 Cyanato NCO (g) 127.02 127.49 ± 0.35 kJ/mol 42.01684 ± 0.00086 22400-26-6*0 Phosgene COCl2 (g) -217.43 -219.13 ± 0.27 kJ/mol 98.9155 ± 0.0020 75-44-5*0 Bromoform CBr3H (g) 74.3 48.1 ± 1.3 kJ/mol 252.7306 ± 0.0031 75-25-2*0 Vinyl chloride CH2CHCl (g) 29.57 22.10 ± 0.34 kJ/mol 62.4979 ± 0.0018 75-01-4*0 Acetone CH3C(O)CH3 (g) -199.45 -216.14 ± 0.36 kJ/mol 58.0791 ± 0.0025 67-64-1*0 Hydrogen fluoride HF (aq) -334.51 ± 0.17 kJ/mol 20.006343 ± 0.000070 7664-39-3*800 Hypobromite [BrO]- (g) -96.24 -103.73 ± 0.55 kJ/mol 95.9039 ± 0.0010 14380-62-2*0 Diazenylium [N2H]+ (g) 1042.78 1039.17 ± 0.73 kJ/mol 29.02087 ± 0.00016 12357-66-3*0 Peroxynitrous acid HOONO (g, cis, cis) -5.99 -14.43 ± 0.36 kJ/mol 63.01288 ± 0.00091 14691-52-2*3 Dioxygenyl fluoride FOO (g) 26.75 25.04 ± 0.27 kJ/mol 50.99720 ± 0.00060 15499-23-7*0 Cyclopropane CH2(CH2CH2) (g) 70.80 53.65 ± 0.46 kJ/mol 42.0797 ± 0.0024 75-19-4*0 Propadienylidene CH2CC (g) 554.45 555.59 ± 0.42 kJ/mol 38.0480 ± 0.0024 60731-10-4*0 Acetyl CH3CO (g) -3.31 -9.97 ± 0.37 kJ/mol 43.0446 ± 0.0016 3170-69-2*0 Methylperoxy CH3OO (g) 22.29 12.54 ± 0.49 kJ/mol 47.0333 ± 0.0010 2143-58-0*0 Ethyl fluoride CH3CH2F (g) -257.30 -272.16 ± 0.37 kJ/mol 48.0595 ± 0.0016 353-36-6*0 Ethyl bromide CH3CH2Br (g) -41.14 -63.09 ± 0.26 kJ/mol 108.9651 ± 0.0019 74-96-4*0 Vinyl fluoride CH2CHF (g) -134.71 -142.51 ± 0.47 kJ/mol 46.0436 ± 0.0016 75-02-5*0 Vinyl bromide CH2CHBr (g) 88.82 74.01 ± 0.59 kJ/mol 106.9492 ± 0.0019 593-60-2*0 2-Bromoethanol BrCH2CH2OH (g) -196.57 -220.63 ± 0.54 kJ/mol 124.9645 ± 0.0019 540-51-2*0 Fluorobenzene C6H5F (g) -99.29 -114.97 ± 0.83 kJ/mol 96.1023 ± 0.0048 462-06-6*0 Nitromethane CH3N(O)O (g) -60.86 -74.76 ± 0.47 kJ/mol 61.0401 ± 0.0010 75-52-5*0 Dioxidanide [HO2]- (g) -88.86 -91.52 ± 0.38 kJ/mol 33.00729 ± 0.00060 14691-59-9*0 Nitrous oxide NNO (g) 85.998 82.568 ± 0.097 kJ/mol 44.01288 ± 0.00033 10024-97-2*0 (E)-Diazene HNNH (g, trans) 207.35 200.20 ± 0.44 kJ/mol 30.02936 ± 0.00020 15626-43-4*0 Hydroxyoxomethylium [HOCO]+ (g) 600.76 597.68 ± 0.43 kJ/mol 45.0169 ± 0.0010 638-71-1*0 Vinylium [C2H3]+ (g) 1119.20 1115.75 ± 0.57 kJ/mol 27.0447 ± 0.0016 14604-48-9*0 Hydroxymethylium [CH2OH]+ (g) 717.85 709.91 ± 0.19 kJ/mol 31.03337 ± 0.00088 18682-95-6*0 Cyanogen NCCN (g) 308.18 310.12 ± 0.43 kJ/mol 52.0349 ± 0.0016 460-19-5*0 Cyanogen iodide ICN (g) 222.47 221.95 ± 0.99 kJ/mol 152.92191 ± 0.00080 506-78-5*0 iso-Propyl CH3CHCH3 (g) 105.28 88.68 ± 0.67 kJ/mol 43.0877 ± 0.0024 2025-55-0*0 Ethynide [C2H]- (g) 277.42 280.83 ± 0.19 kJ/mol 25.0299 ± 0.0016 29075-95-4*0 iso-Butane CH(CH3)3 (g) -106.17 -134.78 ± 0.33 kJ/mol 58.1222 ± 0.0033 75-28-5*0 n-Pentane CH3CH2CH2CH2CH3 (g) -114.47 -146.34 ± 0.31 kJ/mol 72.1488 ± 0.0041 109-66-0*0 2-Chloroethanol ClCH2CH2OH (g) -250.03 -266.74 ± 0.61 kJ/mol 80.5132 ± 0.0019 107-07-3*0 Hypofluorite [FO]- (g) -108.90 -108.73 ± 0.48 kJ/mol 34.99835 ± 0.00030 12763-66-5*0 Hydrogen chloride HCl (aq, 600 H2O) -166.454 ± 0.024 kJ/mol 36.46064 ± 0.00090 7647-01-0*834 Bromoxyl radical BrO (g) 131.12 123.59 ± 0.29 kJ/mol 95.9034 ± 0.0010 15656-19-6*0 Hydroxyamidogen HNOH (g, trans) 101.5 94.7 ± 1.0 kJ/mol 32.02202 ± 0.00034 13940-32-4*1 Nitrate [NO3]- (g) -300.25 -306.72 ± 0.61 kJ/mol 62.00549 ± 0.00090 14797-55-8*0 Water H2O (l) -285.828 ± 0.027 kJ/mol 18.01528 ± 0.00033 7732-18-5*590 Formyl anion [HCO]- (g) 11.62 12.01 ± 0.43 kJ/mol 29.01859 ± 0.00086 57340-31-5*0 Propyl CH3CH2CH2 (g) 117.92 100.81 ± 0.61 kJ/mol 43.0877 ± 0.0024 2143-61-5*0 2-Propynylidyne CCCH (g) 717.95 722.30 ± 0.81 kJ/mol 37.0400 ± 0.0024 53590-28-6*0 Dicarbon monoxide CCO (g, singlet) 454.95 459.28 ± 0.88 kJ/mol 40.0208 ± 0.0016 12071-23-7*2 Methanetetraylbisamidogen NCN (g) 450.39 450.80 ± 0.68 kJ/mol 40.02418 ± 0.00081 2669-76-3*0 Methylene bromide CH2Br2 (g) 24.9 3.5 ± 1.1 kJ/mol 173.8346 ± 0.0022 74-95-3*0 2-Fluoroethanol FCH2CH2OH (g) -406.8 -424.0 ± 1.1 kJ/mol 64.0589 ± 0.0017 371-62-0*0 Phenide [C6H5]- (g) 244.70 231.79 ± 0.43 kJ/mol 77.1044 ± 0.0048 30922-78-2*0 Bromobenzene C6H5Br (g) 126.5 104.5 ± 1.3 kJ/mol 157.0079 ± 0.0049 108-86-1*0 Hydrogen bromide HBr (aq) -120.80 ± 0.16 kJ/mol 80.9119 ± 0.0010 10035-10-6*800 Iodine monochloride ICl (g) 19.024 17.391 ± 0.013 kJ/mol 162.35717 ± 0.00090 7790-99-0*0 Iodotrifluoromethane CF3I (g) -583.99 -589.87 ± 0.54 kJ/mol 195.91038 ± 0.00080 2314-97-8*0 Nitrogen atom cation N+ (g) 1872.905 1875.687 ± 0.024 kJ/mol 14.006191 ± 0.000070 14158-23-7*0 Azido radical NNN (g) 452.24 449.65 ± 0.58 kJ/mol 42.02022 ± 0.00021 12596-60-0*0 Trinitrogen cation [NNN]+ (g) 1519.39 1516.86 ± 0.87 kJ/mol 42.01967 ± 0.00021 12185-03-4*0 Oxonitrate anion [NO]- (g) 87.91 87.94 ± 0.12 kJ/mol 30.00669 ± 0.00031 14967-78-3*0 Carbon monoxide cation [CO]+ (g) 1238.307 1241.586 ± 0.026 kJ/mol 28.00955 ± 0.00085 12144-04-6*0 Nitrosyl ion [NO]+ (g) 984.485 984.479 ± 0.065 kJ/mol 30.00559 ± 0.00031 14452-93-8*0 Nitroxyl H2NO (g) 71.34 64.73 ± 0.85 kJ/mol 32.02202 ± 0.00034 13408-29-2*0 Hydrazoic acid HNNN (g) 297.92 291.62 ± 0.48 kJ/mol 43.02816 ± 0.00022 7782-79-8*0 Ethonium [C2H7]+ (g, bridged C2) 874.54 858.27 ± 0.61 kJ/mol 31.0764 ± 0.0017 24669-33-8*1 Acetylium [CH3CO]+ (g) 667.18 660.02 ± 0.65 kJ/mol 43.0441 ± 0.0016 15762-07-9*0 Hydroxymethylene HCOH (g, trans) 112.40 108.63 ± 0.33 kJ/mol 30.02598 ± 0.00087 19710-56-6*1 Carbonic acid C(O)(OH)2 (g, cis-cis) -602.78 -612.96 ± 0.79 kJ/mol 62.0248 ± 0.0012 463-79-6*1 1-Butene CH2CHCH2CH3 (g) 20.88 -0.08 ± 0.38 kJ/mol 56.1063 ± 0.0032 106-98-9*0 n-Hexane CH3CH2CH2CH2CH2CH3 (g) -130.06 -166.93 ± 0.34 kJ/mol 86.1754 ± 0.0049 110-54-3*0 1-Hydroxyethylium [CH3CHOH]+ (g, anti) 609.14 594.72 ± 0.39 kJ/mol 45.0600 ± 0.0017 18682-96-7*1 Ethoxy CH3CH2O (g, A 2A') 5.41 -9.02 ± 0.52 kJ/mol 45.0605 ± 0.0017 2154-50-9*52 Dicarbon monoxide CCO (g, triplet) 376.30 380.34 ± 0.97 kJ/mol 40.0208 ± 0.0016 12071-23-7*1 Formic acid HC(O)OH (g, anti) -354.76 -362.00 ± 0.38 kJ/mol 46.0254 ± 0.0010 64-18-6*2 Formyloxidanyl HC(O)O (g, 2A1) -124.76 -126.43 ± 0.55 kJ/mol 45.0174 ± 0.0010 16499-21-1*1 Formate [HC(O)O]- (g) -462.11 -465.75 ± 0.55 kJ/mol 45.0180 ± 0.0010 71-47-6*0 Chlorodifluoromethane CHClF2 (g) -476.5 -482.6 ± 1.2 kJ/mol 86.4681 ± 0.0012 75-45-6*0 Fluoromethylene CHF (g, singlet) 148.26 148.54 ± 0.44 kJ/mol 32.01704 ± 0.00080 13453-52-6*2 Fluoroformyl FCO (g) -176.70 -176.12 ± 0.38 kJ/mol 47.00850 ± 0.00085 1871-24-5*0 Benzaldehyde C6H5C(O)H (g) -19.16 -36.96 ± 0.92 kJ/mol 106.1219 ± 0.0056 100-52-7*0 Chlorobenzene C6H5Cl (g) 67.13 52.18 ± 0.61 kJ/mol 112.5566 ± 0.0049 108-90-7*0 Hydrogen chloride HCl (aq) -166.994 ± 0.023 kJ/mol 36.46064 ± 0.00090 7647-01-0*800 Bromonium [HBrH]+ (g) 925.4 914.7 ± 1.2 kJ/mol 81.9193 ± 0.0010 36658-54-5*0 Hydrogen peroxide cation [H2O2]+ (g, trans) 896.87 889.88 ± 0.57 kJ/mol 34.01413 ± 0.00062 12325-10-9*1 Amide [NH2]- (g) 114.88 112.00 ± 0.33 kJ/mol 16.02317 ± 0.00016 17655-31-1*0 Hydrazine H2NNH2 (g) 111.84 97.68 ± 0.49 kJ/mol 32.04524 ± 0.00031 302-01-2*0 Fluoronium [HFH]+ (g) 774.42 771.47 ± 0.85 kJ/mol 21.01373 ± 0.00014 12206-67-6*0 Methanide [CH3]- (g) 146.05 142.61 ± 0.91 kJ/mol 15.03507 ± 0.00083 15194-58-8*0 Trioxidane HOOOH (g, trans) -81.43 -90.27 ± 0.70 kJ/mol 50.01408 ± 0.00091 14699-99-1*1 Ethylidene CH3CH (g, triplet) 361.45 354.45 ± 0.82 kJ/mol 28.0532 ± 0.0016 4218-50-2*1 Peroxyformic acid HC(O)OOH (g, cis) -279.8 -289.1 ± 1.1 kJ/mol 62.0248 ± 0.0012 107-32-4*1 1-Methylethenyl CH3CCH2 (g) 262.90 252.56 ± 0.71 kJ/mol 41.0718 ± 0.0024 15552-77-9*0 Isobutene CH2C(CH3)2 (g) 3.92 -17.15 ± 0.44 kJ/mol 56.1063 ± 0.0032 115-11-7*0 trans-2-Butene CH3CHCHCH3 (g, trans) 9.26 -11.30 ± 0.41 kJ/mol 56.1063 ± 0.0032 624-64-6*0 cis-2-Butene CH3CHCHCH3 (g, cis) 13.95 -7.32 ± 0.42 kJ/mol 56.1063 ± 0.0032 590-18-1*0 1,3-Butadiene CH2CHCHCH2 (g) 125.05 110.57 ± 0.42 kJ/mol 54.0904 ± 0.0032 106-99-0*0 Cyclopentane CH2(CH2CH2CH2CH2) (g) -45.01 -77.58 ± 0.44 kJ/mol 70.1329 ± 0.0041 287-92-3*0 1,3-Cyclopentadiene CH2(CHCHCHCH) (g) 149.88 132.76 ± 0.76 kJ/mol 66.1011 ± 0.0040 542-92-7*0 1-Hydroxyethyl CH3CHOH (g, gauche-syn) -40.65 -54.12 ± 0.86 kJ/mol 45.0605 ± 0.0017 2348-46-1*2 Protonated oxirane [(CH2CH2)OH]+ (g) 725.29 709.12 ± 0.64 kJ/mol 45.0600 ± 0.0017 *38607-31-7*0 Oxoethenyl HCCO (g) 176.85 177.97 ± 0.60 kJ/mol 41.0287 ± 0.0016 51095-15-9*0 Methanediol CH2(OH)2 (g, conrot gauche) -379.05 -393.25 ± 0.95 kJ/mol 48.0413 ± 0.0010 463-57-0*1 Acetyl chloride CH3C(O)Cl (g) -232.68 -241.55 ± 0.33 kJ/mol 78.4973 ± 0.0019 75-36-5*0 Methyl formate HC(O)OCH3 (g, syn-staggered) -344.75 -357.80 ± 0.58 kJ/mol 60.0520 ± 0.0017 107-31-3*1 Trioxidanide [HOOO]- (g, gauche) -121.0 -124.0 ± 1.4 kJ/mol 49.00669 ± 0.00090 89965-38-8*2 Difluorodichloromethane CF2Cl2 (g) -490.69 -495.46 ± 0.97 kJ/mol 120.9129 ± 0.0020 75-71-8*0 Fluorodichloromethane CHFCl2 (g) -278.9 -284.2 ± 1.2 kJ/mol 102.9224 ± 0.0020 75-43-4*0 Trifluoromethylium [CF3]+ (g) 409.00 405.93 ± 0.51 kJ/mol 69.00536 ± 0.00080 18851-76-8*0 Methyl nitrite CH3ONO (g, cis) -55.46 -67.24 ± 0.46 kJ/mol 61.0401 ± 0.0010 624-91-9*2 Dichlorine monoxide ClOCl (g) 79.76 77.95 ± 0.36 kJ/mol 86.9048 ± 0.0018 7791-21-1*0 Chlorine peroxide ClOOCl (g) 134.51 131.28 ± 0.56 kJ/mol 102.9042 ± 0.0019 12292-23-8*0 Iodoxyl radical IO (g) 127.0 125.0 ± 1.1 kJ/mol 142.90387 ± 0.00030 14696-98-1*0 Dinitrogen cation [N2]+ (g) 1503.311 1503.312 ± 0.0011 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 Nitrogen sesquioxide ONNO2 (g) 90.72 86.15 ± 0.15 kJ/mol 76.01168 ± 0.00091 10544-73-7*0 Ammonium [NH4]+ (g) 643.05 631.74 ± 0.21 kJ/mol 18.03795 ± 0.00029 14798-03-9*0 Chloronium [HClH]+ (g) 881.29 878.19 ± 0.97 kJ/mol 37.46803 ± 0.00091 36658-55-6*0 Ammonium [NH4]+ (aq) -133.077 ± 0.056 kJ/mol 18.03795 ± 0.00029 14798-03-9*800 Hydrazyl N2H3 (g) 235.28 224.62 ± 0.83 kJ/mol 31.03730 ± 0.00025 13598-46-4*0 Dioxygen difluoride FOOF (g) 33.66 29.93 ± 0.50 kJ/mol 69.99561 ± 0.00060 7783-44-0*0 Ethylidene CH3CH (g, singlet) 373.93 366.70 ± 0.86 kJ/mol 28.0532 ± 0.0016 4218-50-2*2 Hydrogen isocyanide cation [HNC]+ (g) 1352.7 1352.7 ± 1.2 kJ/mol 27.02483 ± 0.00081 74158-11-5*0 Propargylenide [HCCCH]- (g, transoid 2B) 434.6 437.1 ± 1.1 kJ/mol 38.0485 ± 0.0024 82906-05-6*1 2-Hydroxyethyl CH2CH2OH (g, gauche-anti) -10.04 -22.67 ± 0.85 kJ/mol 45.0605 ± 0.0017 4422-54-2*2 Dimethyl ether CH3OCH3 (g) -166.50 -184.01 ± 0.44 kJ/mol 46.0684 ± 0.0017 115-10-6*0 Methanediol CH2(OH)2 (g, disrot gauche) -368.51 -381.66 ± 0.99 kJ/mol 48.0413 ± 0.0010 463-57-0*2 Dichloride [Cl2]- (g) -230.4 -229.3 ± 1.4 kJ/mol 70.9059 ± 0.0018 12595-89-0*0 Chlorine dioxide OClO (g) 101.03 98.56 ± 0.30 kJ/mol 67.4515 ± 0.0011 10049-04-4*0 Hydroperoxonium [H2OOH]+ (g, trans) 738.17 727.91 ± 0.98 kJ/mol 35.02207 ± 0.00064 70850-26-9*1 Formyl fluoride HFCO (g) -378.72 -382.31 ± 0.33 kJ/mol 48.01644 ± 0.00086 1493-02-3*0 Nitric acid HNO3 (aq) -206.63 ± 0.18 kJ/mol 63.01288 ± 0.00091 7697-37-2*800 Hydrogen fluoride HF (aq, 20 H2O) -321.06 ± 0.17 kJ/mol 20.006343 ± 0.000070 7664-39-3*818 Oxoammoniumyl [HNO]+ (g) 1092.62 1089.69 ± 0.67 kJ/mol 31.01353 ± 0.00032 63559-87-5*0 Difluoride [F2]- (g) -290.8 -290.0 ± 1.4 kJ/mol 37.9973550 ± 0.0000010 12184-85-9*0 Peroxynitrous acid HOONO (g, trans, perp) 7.67 0.59 ± 0.40 kJ/mol 63.01288 ± 0.00091 14691-52-2*1 Vinylidene CCH2 (g) 411.29 412.20 ± 0.33 kJ/mol 26.0373 ± 0.0016 2143-69-3*0 Ethylidyne CH3C (g) 508.58 504.88 ± 0.87 kJ/mol 27.0452 ± 0.0016 67624-57-1*0 Ethylidyne CH3C (g, quartet) 640.6 636.1 ± 1.2 kJ/mol 27.0452 ± 0.0016 67624-57-1*2 Iminomethyl cation [HCNH]+ (g) 953.3 949.3 ± 1.5 kJ/mol 28.03277 ± 0.00082 196216-36-1*0 Chlorine superoxide ClOO (g) 103.82 102.73 ± 0.37 kJ/mol 67.4515 ± 0.0011 17376-09-9*0 Water dimer (H2O)2 (g) -491.082 -499.121 ± 0.053 kJ/mol 36.03056 ± 0.00066 25655-83-8*0 iso-Propylium [CH3CHCH3]+ (g) 822.88 805.62 ± 0.26 kJ/mol 43.0871 ± 0.0024 19252-53-0*0 Trioxidane HOOOH (g, cis) -72.03 -80.52 ± 0.81 kJ/mol 50.01408 ± 0.00091 14699-99-1*2 1-Propenyl CH3CHCH (g, cis) 277.98 267.19 ± 0.79 kJ/mol 41.0718 ± 0.0024 6067-68-1*2 1-Propynyl CH3CC (g) 529.00 526.64 ± 0.81 kJ/mol 39.0559 ± 0.0024 89342-91-6*0 Propargylenide [HCCCH]- (g, cisoid 2A) 437.0 439.5 ± 1.1 kJ/mol 38.0485 ± 0.0024 82906-05-6*2 2-Propyn-1-ylium-1-ylidene [CCCH]+ (g) 1598.0 1602.9 ± 1.3 kJ/mol 37.0395 ± 0.0024 75104-46-0*0 2-Butyne CH3CCCH3 (g) 158.96 146.00 ± 0.59 kJ/mol 54.0904 ± 0.0032 503-17-3*0 1-Butyne CH3CH2CCH (g) 179.36 165.77 ± 0.67 kJ/mol 54.0904 ± 0.0032 107-00-6*0 iso-Pentane CH3CH2CH(CH3)2 (g) -119.22 -153.27 ± 0.44 kJ/mol 72.1488 ± 0.0041 78-78-4*0 Chlorine fluoride ClF (g) -55.612 -55.707 ± 0.055 kJ/mol 54.45110 ± 0.00090 7790-89-8*0 2-Hydroxyethyl CH2CH2OH (g, staggered-anti) -5.1 -17.5 ± 1.2 kJ/mol 45.0605 ± 0.0017 4422-54-2*3 Vinoxy CH2CHO (g) 22.46 15.62 ± 0.77 kJ/mol 43.0446 ± 0.0016 6912-06-7*0 Acetyl anion [CH3CO]- (g) -43.8 -49.4 ± 1.3 kJ/mol 43.0452 ± 0.0016 78944-68-0*0 Ketene CH2CO (g, triplet) 182.5 177.5 ± 1.1 kJ/mol 42.0367 ± 0.0016 463-51-4*1 Formic acid HC(O)OH (g) -371.12 -378.42 ± 0.22 kJ/mol 46.0254 ± 0.0010 64-18-6*0 Hydroxyformyl HOCO (g, cis) -174.04 -177.07 ± 0.51 kJ/mol 45.0174 ± 0.0010 2564-86-5*2 Hydroxyformyl anion [HOCO]- (g, cis) -319.36 -322.13 ± 0.58 kJ/mol 45.0180 ± 0.0010 78944-70-4*2 Fluorotrichloromethane CCl3F (g) -286.9 -290.1 ± 1.2 kJ/mol 137.3672 ± 0.0028 75-69-4*0 Bromotrichloromethane CCl3Br (g) -33.82 -42.97 ± 0.71 kJ/mol 198.2728 ± 0.0030 75-62-7*0 Difluoromethylene CF2 (g) -193.99 -193.51 ± 0.38 kJ/mol 50.00751 ± 0.00080 2154-59-8*0 Fluoromethylene CHF (g, triplet) 210.12 210.45 ± 0.68 kJ/mol 32.01704 ± 0.00080 13453-52-6*1 Hexafluoroethane CF3CF3 (g) -1334.5 -1342.8 ± 1.5 kJ/mol 138.0118 ± 0.0016 76-16-4*0 1,1-Difluoroethane CHF2CH3 (g) -489.09 -502.81 ± 0.65 kJ/mol 66.0500 ± 0.0016 75-37-6*0 2-Hydrotrioxy OO(H)O (g) 300.9 295.2 ± 1.1 kJ/mol 49.00614 ± 0.00090 *12500-78-6*0 1,1-Difluoroethene CH2CF2 (g) -343.72 -350.78 ± 0.85 kJ/mol 64.0341 ± 0.0016 75-38-7*0 Tricarbon dioxide OCCCO (g) -96.2 -94.1 ± 1.2 kJ/mol 68.0309 ± 0.0025 504-64-3*0 Iodobenzene C6H5I (g) 177.6 161.6 ± 1.0 kJ/mol 204.0084 ± 0.0048 591-50-4*0 Iodine monobromide IBr (g) 49.717 40.770 ± 0.067 kJ/mol 206.8085 ± 0.0010 7789-33-5*0 Nitrosyl nitrite ONONO (g, sym) 92.6 87.5 ± 1.2 kJ/mol 76.01168 ± 0.00091 122413-35-8*1 Nitroxyl NO3 (g) 79.38 74.13 ± 0.19 kJ/mol 62.00494 ± 0.00090 12033-49-7*0 Isodiazene H2NN (g) 307.99 300.93 ± 0.75 kJ/mol 30.02936 ± 0.00020 28647-38-3*0 Nitryl hydride HN(O)O (g) -37.2 -44.2 ± 1.5 kJ/mol 47.01348 ± 0.00061 90266-90-3*0 Carbon atom cation C+ (g) 1797.854 1803.452 ± 0.050 kJ/mol 12.01015 ± 0.00080 14067-05-1*0 Methyliumyl [CH2]+ (g) 1393.09 1393.95 ± 0.13 kJ/mol 14.02603 ± 0.00081 15091-72-2*0 Oxygen atom O (g, singlet) 436.666 438.523 ± 0.0021 kJ/mol 15.99940 ± 0.00030 17778-80-2*2 Methyliumylidene [CH]+ (g) 1619.758 1623.102 ± 0.057 kJ/mol 13.01809 ± 0.00080 24361-82-8*0 Methylidyne anion [CH]- (g) 475.47 478.79 ± 0.91 kJ/mol 13.01919 ± 0.00080 28604-54-8*0 Ozonide [OOO]- (g) -58.48 -60.83 ± 0.21 kJ/mol 47.99875 ± 0.00090 12596-80-4*0 (E)-Iminomethyl HCNH (g, trans) 275.92 272.30 ± 0.84 kJ/mol 28.03332 ± 0.00082 54980-10-8*0 Nitrilomethylium [CN]+ (g) 1778.3 1781.8 ± 1.2 kJ/mol 26.01689 ± 0.00080 12539-57-0*0 Fluoroacetylene HCCF (g) 104.73 105.45 ± 0.41 kJ/mol 44.0277 ± 0.0016 2713-09-9*0 Chloroacetylene HCCCl (g) 228.3 229.2 ± 1.1 kJ/mol 60.4820 ± 0.0018 593-63-5*0 Methanol cation [CH3OH]+ (g) 857.08 846.75 ± 0.33 kJ/mol 32.04131 ± 0.00090 12538-91-9*0 Methyloxonium [CH3OH2]+ (g) 589.9 575.7 ± 1.2 kJ/mol 33.04925 ± 0.00092 17836-08-7*0 Hydroxyde [OH]- (aq) -230.012 ± 0.029 kJ/mol 17.00789 ± 0.00031 14280-30-9*800 Oxidanylium [OH]+ (g) 1293.189 1293.218 ± 0.035 kJ/mol 17.00679 ± 0.00031 12259-29-9*0 Carbonic acid C(O)(OH)2 (g, cis-trans) -596.93 -607.04 ± 0.85 kJ/mol 62.0248 ± 0.0012 463-79-6*2 Carbonic acid C(O)(OH)2 (g, trans-trans) -561.70 -570.55 ± 0.98 kJ/mol 62.0248 ± 0.0012 463-79-6*3 1,2-Propadienyl anion [CH2CCH]- (g) 265.85 262.65 ± 0.72 kJ/mol 39.0565 ± 0.0024 64066-06-4*0 1-Propynyl anion [CH3CC]- (g) 265.06 261.59 ± 0.81 kJ/mol 39.0565 ± 0.0024 36147-87-2*0 Bromine monochloride BrCl (g) 21.880 14.437 ± 0.060 kJ/mol 115.3567 ± 0.0013 13863-41-7*0 neo-Pentane C(CH3)4 (g) -134.64 -167.52 ± 0.41 kJ/mol 72.1488 ± 0.0041 463-82-1*0 Cyclohexane CH2(CH2CH2CH2CH2CH2) (g) -83.59 -123.15 ± 0.36 kJ/mol 84.1595 ± 0.0049 110-82-7*0 2-Hydroxyethylium [CH2CH2OH]+ (g, staggered-anti) 1019.6 1006.8 ± 1.6 kJ/mol 45.0600 ± 0.0017 38607-31-7*3 Vinyl alcohol CH2CHOH (g, syn) -112.55 -123.86 ± 0.84 kJ/mol 44.0526 ± 0.0017 557-75-5*1 Ethynol HCCOH (g) 94.9 92.8 ± 1.3 kJ/mol 42.0367 ± 0.0016 32038-79-2*0 Hydroxyformyl anion [HOCO]- (g, trans) -313.53 -315.48 ± 0.59 kJ/mol 45.0180 ± 0.0010 78944-70-4*1 1-Propanol CH3CH2CH2OH (g) -231.38 -255.22 ± 0.26 kJ/mol 60.0950 ± 0.0025 71-23-8*0 2-Propanol CH3CH(OH)CH3 (g) -248.77 -272.87 ± 0.36 kJ/mol 60.0950 ± 0.0025 67-63-0*0 Acetic acid CH3C(O)OH (g, syn) -418.38 -432.50 ± 0.54 kJ/mol 60.0520 ± 0.0017 64-19-7*1 Ethylene glycol (CH2OH)2 (g) -369.80 -389.43 ± 0.49 kJ/mol 62.0678 ± 0.0018 107-21-1*0 Fluorochloromethane CH2FCl (g) -256.4 -263.6 ± 1.3 kJ/mol 68.4777 ± 0.0012 593-70-4*0 Chlorine atom cation Cl+ (g) 1370.806 1372.602 ± 0.0011 kJ/mol 35.45215 ± 0.00090 24203-47-2*0 Trioxidanyl HOOO (g, trans) 25.31 23.33 ± 0.13 kJ/mol 49.00614 ± 0.00090 12500-78-6*1 1,3-Butadiyne HCCCCH (g) 458.57 460.30 ± 0.86 kJ/mol 50.0587 ± 0.0032 460-12-8*0 Toluene C6H5CH3 (g) 73.56 50.27 ± 0.36 kJ/mol 92.1384 ± 0.0056 108-88-3*0 Fluorobenzene cation [C6H5F]+ (g) 788.69 774.00 ± 0.83 kJ/mol 96.1018 ± 0.0048 34468-25-2*0 Nitromethyl CH2N(O)O (g) 138.8 129.4 ± 1.2 kJ/mol 60.0321 ± 0.0010 16787-85-2*0 Dinitrogen pentoxide O2NONO2 (g) 24.41 14.84 ± 0.35 kJ/mol 108.0105 ± 0.0015 10102-03-1*0 Water anion [(H)(OH)]- (g, vdW ?) 30.5 29.0 ± 2.5 kJ/mol 18.01583 ± 0.00033 12259-30-2*100 Bromonium Br+ (g) 1257.777 1251.714 ± 0.056 kJ/mol 79.90345 ± 0.00100 22541-56-6*0 Peroxynitric acid HOON(O)O (g) -42.6 -54.1 ± 1.3 kJ/mol 79.0123 ± 0.0012 26404-66-0*0 Nitrosyl chloride ClNO (g) 54.451 52.549 ± 0.067 kJ/mol 65.45884 ± 0.00095 2696-92-6*0 Carbon dioxide CO2 (g, triplet) 49.48 50.33 ± 0.99 kJ/mol 44.00950 ± 0.00100 124-38-9*1 Methane cation [CH4]+ (g) 1150.84 1144.45 ± 0.25 kJ/mol 16.04191 ± 0.00085 20741-88-2*0 Ethonium [C2H7]+ (g) 874.54 858.30 ± 0.61 kJ/mol 31.0764 ± 0.0017 24669-33-8*0 Vinyl anion [C2H3]- (g) 237.24 232.82 ± 0.84 kJ/mol 27.0458 ± 0.0016 25012-81-1*0 Acetylene cation [HCCH]+ (g) 1328.85 1328.18 ± 0.14 kJ/mol 26.0367 ± 0.0016 25641-79-6*0 Bromide Br- (aq) -120.80 ± 0.16 kJ/mol 79.90455 ± 0.00100 24959-67-9*800 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) 456.8 452.7 ± 1.4 kJ/mol 27.0458 ± 0.0016 117768-70-4*0 Vinylidene anion [CCH2]- (g) 364.15 363.97 ± 0.62 kJ/mol 26.0378 ± 0.0016 66295-36-1*0 Iodide I- (aq) -56.829 ± 0.090 kJ/mol 126.905019 ± 0.000030 20461-54-5*800 Ethynylium [C2H]+ (g) 1687.59 1690.93 ± 0.16 kJ/mol 25.0288 ± 0.0016 16456-59-0*0 Aminomethyl CH2NH2 (g) 159.40 148.51 ± 0.58 kJ/mol 30.04920 ± 0.00085 10507-29-6*0 Methylamidogen anion [CH3NH]- (g) 145.99 134.64 ± 0.76 kJ/mol 30.04975 ± 0.00085 54448-39-4*0 Methyleneamidogen H2CN (g) 242.22 238.56 ± 0.85 kJ/mol 28.03332 ± 0.00082 15845-29-1*0 (Z)-Iminomethyl HCNH (g, cis) 294.5 291.0 ± 1.2 kJ/mol 28.03332 ± 0.00082 54980-11-9*0 Methyloxoniumylidene [CH3O]+ (g) 1062.43 1054.62 ± 0.72 kJ/mol 31.03337 ± 0.00088 58157-09-8*0 Hydroxymethylene HCOH (g, cis) 130.86 127.11 ± 0.34 kJ/mol 30.02598 ± 0.00087 19710-56-6*2 Hydroxymethylene cation [HCOH]+ (g, trans) 971.9 968.3 ± 1.3 kJ/mol 30.02543 ± 0.00087 135395-06-1*1 Hydrogen difluoride cation [FFH]+ (g) 1173.5 1170.6 ± 1.7 kJ/mol 39.004198 ± 0.000070 *126950-54-7*0 Oxoniumyl ion [H2O]+ (g) 978.472 975.569 ± 0.029 kJ/mol 18.01473 ± 0.00033 56583-62-1*0 Isoformyl COH (g) 217.30 217.69 ± 0.67 kJ/mol 29.01804 ± 0.00086 71080-92-7*0 Azide ion [NNN]- (g) 193.63 190.05 ± 0.89 kJ/mol 42.02077 ± 0.00021 14343-69-2*0 1-Propenyl CH3CHCH (g, trans) 280.02 269.21 ± 0.81 kJ/mol 41.0718 ± 0.0024 6067-68-1*1 Cyclopropene CH2(CHCH) (g) 292.54 283.82 ± 0.54 kJ/mol 40.0639 ± 0.0024 2781-85-3*0 Cyclobutane CH2(CH2CH2CH2) (g) 52.17 27.63 ± 0.47 kJ/mol 56.1063 ± 0.0032 287-23-0*0 Dioxidenium [HO2]+ (g) 1110.87 1107.98 ± 0.11 kJ/mol 33.00619 ± 0.00060 12207-52-2*0 n-Heptane CH3(CH2)5CH3 (g) -145.65 -187.53 ± 0.48 kJ/mol 100.2019 ± 0.0057 142-82-5*0 n-Octane CH3(CH2)6CH3 (g) -161.43 -208.27 ± 0.67 kJ/mol 114.2285 ± 0.0065 111-65-9*0 1-Hydroxyethylium [CH3CHOH]+ (g, syn) 611.1 596.6 ± 1.2 kJ/mol 45.0600 ± 0.0017 18682-96-7*2 1H-Triazirin-1-yl N(NN) (g) 585.9 584.1 ± 2.0 kJ/mol 42.02022 ± 0.00021 912535-95-6*0 Vinyl alcohol CH2CHOH (g, anti) -108.10 -118.62 ± 0.88 kJ/mol 44.0526 ± 0.0017 557-75-5*2 Vinyl alcohol cation [CH2CHOH]+ (g, anti) 779.2 768.0 ± 1.2 kJ/mol 44.0520 ± 0.0017 57239-63-1*2 Oxiranyl CH2(CHO) (g) 172.8 164.5 ± 1.4 kJ/mol 43.0446 ± 0.0016 31586-84-2*0 Oxiranylium [CH2(CHO)]+ (g, singlet) 901.6 893.6 ± 1.4 kJ/mol 43.0441 ± 0.0016 57789-76-1*2 C=O=C COC (g, triplet) 653.3 657.6 ± 2.2 kJ/mol 40.0208 ± 0.0016 *12071-23-7*1 C=O=C COC (g, singlet) 721.5 725.9 ± 1.6 kJ/mol 40.0208 ± 0.0016 *12071-23-7*2 Oxirene O(CHCH) (g, singlet) 272.81 272.12 ± 0.98 kJ/mol 42.0367 ± 0.0016 157-18-6*2 Oxirene O(CHCH) (g, t-triplet) 388.7 384.5 ± 2.6 kJ/mol 42.0367 ± 0.0016 157-18-6*11 Formic acid cation [HC(O)OH]+ (g, syn) 721.86 714.77 ± 0.26 kJ/mol 46.0248 ± 0.0010 50614-05-6*1 Dioxirane CH2(OO) (g) 9.41 1.74 ± 0.54 kJ/mol 46.0254 ± 0.0010 157-26-6*0 Formyloxidanyl HC(O)O (g, 2B2) -120.94 -124.29 ± 0.55 kJ/mol 45.0174 ± 0.0010 16499-21-1*2 Isofulminic acid HCNO (g) 170.91 169.45 ± 0.49 kJ/mol 43.02478 ± 0.00086 51060-05-0*0 Trioxidanylium [HOOO]+ (g, trans) 1070.2 1063.9 ± 1.3 kJ/mol 49.00559 ± 0.00090 74241-49-9*1 Methyl formate HC(O)OCH3 (g, anti-eclipsed) -324.6 -337.1 ± 1.6 kJ/mol 60.0520 ± 0.0017 107-31-3*2 Methyl iodide CH3I (l) -12.20 ± 0.19 kJ/mol 141.93899 ± 0.00083 74-88-4*590 Difluoromethylene CF2 (g, triplet) 43.20 43.92 ± 0.38 kJ/mol 50.00751 ± 0.00080 2154-59-8*1 Difluoromethylene CF2 (g, singlet) -193.99 -193.51 ± 0.38 kJ/mol 50.00751 ± 0.00080 2154-59-8*2 Ethyl iodide CH3CH2I (l) -9.40 -39.26 ± 0.49 kJ/mol 155.9656 ± 0.0016 75-03-6*500 Fluoro(fluorooxy)methylene FCOF (g, cis) -135.8 -137.0 ± 2.0 kJ/mol 66.00691 ± 0.00085 479587-30-9*2 Dibromophosgene COBr2 (g) -97.98 -113.91 ± 0.37 kJ/mol 187.8181 ± 0.0022 593-95-3*0 Fluoride F- (aq) -334.51 ± 0.17 kJ/mol 18.99895178 ± 0.00000050 16984-48-8*800 Benzene C6H6 (cr,l) 50.72 49.17 ± 0.25 kJ/mol 78.1118 ± 0.0048 71-43-2*500 Benzoyl fluoride C6H5C(O)F (g) -288.0 -304.4 ± 1.5 kJ/mol 124.1124 ± 0.0056 455-32-3*0 (E)-Diazene cation [HNNH]+ (g, trans) 1132.58 1125.67 ± 0.67 kJ/mol 30.02881 ± 0.00020 59952-06-6*0 (E)-Diazene anion [HNNH]- (g, trans) 269.3 262.4 ± 1.7 kJ/mol 30.02991 ± 0.00020 *59952-06-6*0 (Z)-Diazene HNNH (g, cis) 229.21 222.07 ± 0.64 kJ/mol 30.02936 ± 0.00020 15626-42-3*0 Diazenyl N2H (g) 252.25 249.33 ± 0.48 kJ/mol 29.02142 ± 0.00016 36882-13-0*0 Hydroxyaminiumyl [NOH]+ (g) 1160.6 1157.7 ± 1.3 kJ/mol 31.01353 ± 0.00032 63559-88-6*0 Hydroxyamidogen HNOH (g, cis) 123.5 117.0 ± 1.4 kJ/mol 32.02202 ± 0.00034 13940-32-4*2 Hydroxyaminylium [HNOH]+ (g, trans) 1020.2 1013.0 ± 1.9 kJ/mol 32.02147 ± 0.00034 66097-71-0*1 Triiodide ion [I3]- (aq) -51.36 ± 0.80 kJ/mol 380.713959 ± 0.000090 14900-04-0*800 Dioxyamidogen HNOO (g, cis) 240.4 233.7 ± 1.8 kJ/mol 47.01348 ± 0.00061 71843-95-3*2 Peroxynitrous acid HOONO (g, cis, perp) -0.35 -7.40 ± 0.53 kJ/mol 63.01288 ± 0.00091 14691-52-2*2 Dioxiranylidene C(OO) (g) 190.6 191.4 ± 1.3 kJ/mol 44.00950 ± 0.00100 138832-57-2*0 Deuterium atom D (g) 219.804 221.717 ± 0.000 kJ/mol 2.01410177800 ± 0.00000000040 16873-17-9*0 Hypoiodite [IO]- (g) -102.5 -104.4 ± 1.2 kJ/mol 142.90442 ± 0.00030 15065-65-3*0 Methylene anion [CH2]- (g) 328.48 328.91 ± 0.51 kJ/mol 14.02713 ± 0.00081 50928-07-9*0 Methylidyne CH (g, doublet) 592.78 596.12 ± 0.11 kJ/mol 13.01864 ± 0.00080 3315-37-5*1 Hydrogen fluoride HF (aq, 40 H2O) -321.15 ± 0.17 kJ/mol 20.006343 ± 0.000070 7664-39-3*821 Ethylidyne CH3C (g, doublet) 508.58 504.88 ± 0.87 kJ/mol 27.0452 ± 0.0016 67624-57-1*1 Trioxodinitrate anion [ONNO2]- (g, vdW) -104.4 -108.4 ± 2.3 kJ/mol 76.01223 ± 0.00091 194856-62-7*100 Aminomethylium [CH2NH2]+ (g) 763.9 752.0 ± 1.8 kJ/mol 30.04865 ± 0.00085 488821-23-4*0 Methylamidogen CH3NH (g) 187.86 177.13 ± 0.61 kJ/mol 30.04920 ± 0.00085 15622-51-2*0 Aminomethylene HCNH2 (g) 246.6 238.8 ± 1.6 kJ/mol 29.04126 ± 0.00083 35430-17-2*0 Methylimidogen H3CN (g) 323.8 316.0 ± 1.6 kJ/mol 29.04126 ± 0.00083 27770-42-9*0 Methyleneamidogen anion [H2CN]- (g) 193.1 189.3 ± 1.1 kJ/mol 28.03387 ± 0.00082 28892-56-0*0 Aminomethylidyne CNH2 (g) 372.2 368.7 ± 1.4 kJ/mol 28.03332 ± 0.00082 84654-89-7*0 Hydrogen isocyanide HNC (g) 191.79 192.18 ± 0.47 kJ/mol 27.02538 ± 0.00081 6914-07-4*0 Cyanide [CN]- (g) 63.958 67.244 ± 0.095 kJ/mol 26.01799 ± 0.00080 57-12-5*0 Methyleneoxonium CH2OH2 (g) 154.6 146.3 ± 1.4 kJ/mol 32.04186 ± 0.00090 177788-17-9*0 Hydroxymethylene HCOH (g, gauche triplet) 219.0 216.1 ± 1.1 kJ/mol 30.02598 ± 0.00087 19710-56-6*3 Hydroxymethylene anion [HCOH]- (g, trans) 147.4 144.4 ± 1.4 kJ/mol 30.02653 ± 0.00087 207914-87-2*1 Dinitrogen tetraoxide O2NNO2 (g) 20.15 10.86 ± 0.14 kJ/mol 92.0111 ± 0.0012 10544-72-6*0 Hydroxymethyliumylidene [COH]+ (g) 986.13 987.77 ± 0.80 kJ/mol 29.01749 ± 0.00086 60528-75-8*0 Isoformyl anion [(CO)(H)]- (g, vdW singlet ?) 55.8 58.4 ± 1.8 kJ/mol 29.01859 ± 0.00086 81747-63-9*1 Propylium [CH3CH2CH2]+ (g) 856.87 838.65 ± 0.83 kJ/mol 43.0871 ± 0.0024 19252-52-9*0 Cyclopropyl CH(CH2CH2) (g) 302.8 290.2 ± 1.6 kJ/mol 41.0718 ± 0.0024 2417-82-5*0 Cycloprop-1-enyl CH2(CHC) (g) 528.11 523.53 ± 0.78 kJ/mol 39.0559 ± 0.0024 19528-44-0*0 Cycloprop-2-enyl CH(CHCH) (g) 491.03 486.42 ± 0.77 kJ/mol 39.0559 ± 0.0024 28933-84-8*0 Cyclopropenylidene C(CHCH) (g) 497.07 496.12 ± 0.47 kJ/mol 38.0480 ± 0.0024 16165-40-5*0 2-Propynylidyne anion [CCCH]- (g) 539.97 544.82 ± 0.84 kJ/mol 37.0406 ± 0.0024 82893-67-2*0 Cyclopropynyl CH(CC) (g) 710.7 714.8 ± 1.1 kJ/mol 37.0400 ± 0.0024 119178-99-3*0 n-Butyl CH3CH2CH2CH2 (g) 101.48 78.25 ± 0.98 kJ/mol 57.1143 ± 0.0033 2492-36-6*0 Methylcyclopropane CH3CH(CH2CH2) (g) 47.5 24.3 ± 1.3 kJ/mol 56.1063 ± 0.0032 594-11-6*0 Cyclobutene CH2(CH2CHCH) (g) 176.79 159.74 ± 0.93 kJ/mol 54.0904 ± 0.0032 822-35-5*0 Oxygen cation monohydrate [(HOH)O]+ (g) 1153.2 1147.7 ± 3.3 kJ/mol 34.01413 ± 0.00062 *31748-17-1*0 Oxygen anion monohydrate [(HOH)O]- (g) -239.1 -244.3 ± 3.0 kJ/mol 34.01523 ± 0.00062 31748-17-1*0 Vinyl alcohol cation [CH2CHOH]+ (g, syn) 787.30 776.18 ± 0.99 kJ/mol 44.0520 ± 0.0017 57239-63-1*1 Vinoxy cation [CH2CHO]+ (g, triplet) 1020.2 1013.2 ± 1.6 kJ/mol 43.0441 ± 0.0016 *35731-40-9*1 Vinoxide [CH2CHO]- (g) -153.55 -160.60 ± 0.77 kJ/mol 43.0452 ± 0.0016 35731-40-9*0 Acetic acid CH3C(O)OH (aq) -485.18 ± 0.23 kJ/mol 60.0520 ± 0.0017 64-19-7*800 Ketene CH2CO (g, singlet) -45.45 -48.57 ± 0.13 kJ/mol 42.0367 ± 0.0016 463-51-4*2 COC vdW (CO)(C) (g, triplet) 589.8 598.5 ± 1.8 kJ/mol 40.0208 ± 0.0016 *12071-24-8*1 Oxirene O(CHCH) (g, c-triplet) 390.8 386.6 ± 2.7 kJ/mol 42.0367 ± 0.0016 157-18-6*12 Methylperoxy anion [CH3OO]- (g) -89.79 -99.94 ± 0.67 kJ/mol 47.0339 ± 0.0010 35683-44-4*0 Formyloxoniumylidene [HC(O)O]+ (g) 1016.9 1013.5 ± 1.3 kJ/mol 45.0169 ± 0.0010 54375-27-8*0 Dioxymethylene HCOO (g, trans) 363.6 361.2 ± 2.6 kJ/mol 45.0174 ± 0.0010 438586-67-5*1 Trioxidaniumyl [HOOOH]+ (g, t, t) 927.1 917.8 ± 1.3 kJ/mol 50.01353 ± 0.00091 161321-37-5*2 Cyanic acid HOCN (g) -12.21 -14.92 ± 0.49 kJ/mol 43.02478 ± 0.00086 420-05-3*0 Fulminic acid HONC (g) 235.37 233.67 ± 0.48 kJ/mol 43.02478 ± 0.00086 506-85-4*0 Isocyanate [NCO]- (g) -221.11 -221.33 ± 0.54 kJ/mol 42.01739 ± 0.00086 71000-82-3*0 Nitrosomethylidyne CNO (g) 389.4 390.7 ± 1.5 kJ/mol 42.01684 ± 0.00086 82267-15-0*0 Oxazirinyl C(NO) (g) 449.9 450.7 ± 1.5 kJ/mol 42.01684 ± 0.00086 228850-18-8*0 Dimethylamine (CH3)2NH (g) 5.91 -15.99 ± 0.67 kJ/mol 45.0837 ± 0.0017 124-40-3*0 Trimethylamine (CH3)3N (g) 4.47 -24.08 ± 0.63 kJ/mol 59.1103 ± 0.0025 75-50-3*0 Isocyanogen CNCN (g) 410.7 413.1 ± 1.6 kJ/mol 52.0349 ± 0.0016 83951-85-3*0 Diisocyanogen CNNC (g) 610.1 613.0 ± 1.7 kJ/mol 52.0349 ± 0.0016 78800-21-2*0 Fluorosyl ion [FO]+ (g) 1342.62 1342.57 ± 0.78 kJ/mol 34.99725 ± 0.00030 12763-67-6*0 Cyanoamidogen HNCN (g) 324.7 322.3 ± 1.7 kJ/mol 41.03212 ± 0.00082 12347-01-2*0 Oxywater (H2O)O (g) 65.0 58.5 ± 1.2 kJ/mol 34.01468 ± 0.00062 171363-09-0*0 Bromodichloromethane CHCl2Br (g) -38.6 -50.3 ± 1.3 kJ/mol 163.8280 ± 0.0022 75-27-4*0 Chlorous acid HOClO (g) 25.67 20.61 ± 0.67 kJ/mol 68.4594 ± 0.0011 13898-47-0*0 Difluorodibromomethane CF2Br2 (g) -366.7 -384.4 ± 1.4 kJ/mol 209.8155 ± 0.0022 75-61-6*0 Dichlorodibromomethane CCl2Br2 (g) 19.6 3.9 ± 1.5 kJ/mol 242.7241 ± 0.0028 594-18-3*0 Bromodifluoromethane CHF2Br (g) -410.92 -424.11 ± 0.49 kJ/mol 130.9194 ± 0.0013 1511-62-2*0 1,2-Difluoroethane CH2FCH2F (g) -434.51 -447.94 ± 0.86 kJ/mol 66.0500 ± 0.0016 624-72-6*0 2-Hydrotrioxy anion [OO(H)O]- (g) 27.6 21.9 ± 1.2 kJ/mol 49.00669 ± 0.00090 *89965-38-8*0 1,2-Difluoroacetylene FCCF (g) 2.45 5.27 ± 0.65 kJ/mol 62.0182 ± 0.0016 689-99-6*0 Fluoro(fluorooxy)methylene FCOF (g, trans) -38.9 -40.4 ± 1.9 kJ/mol 66.00691 ± 0.00085 479587-30-9*1 Chloroformyl ClCO (g) -21.93 -20.54 ± 0.49 kJ/mol 63.4628 ± 0.0012 2602-42-8*0 Phenylium [C6H5]+ (g, triplet) 1251.6 1239.4 ± 3.3 kJ/mol 77.1034 ± 0.0048 17333-73-2*1 Chlorobenzene cation [C6H5Cl]+ (g) 942.47 928.55 ± 0.61 kJ/mol 112.5561 ± 0.0049 55450-32-3*0 Chlorobenzene C6H5Cl (cr,l) 11.22 ± 0.59 kJ/mol 112.5566 ± 0.0049 108-90-7*500 Bromobenzene cation [C6H5Br]+ (g) 994.7 973.3 ± 1.3 kJ/mol 157.0074 ± 0.0049 55450-33-4*0 Iodobenzene C6H5I (cr,l) 112.7 112.8 ± 1.1 kJ/mol 204.0084 ± 0.0048 591-50-4*500 2-Hydrotrioxy cation [OO(H)O]+ (g) 1297.8 1291.1 ± 1.3 kJ/mol 49.00559 ± 0.00090 *74241-49-9*0 Methyl nitrite CH3ONO (g, cis-trans equilib) -55.46 -66.13 ± 0.46 kJ/mol 61.0401 ± 0.0010 624-91-9*0 1,2-Dichloroethane (CClH2)2 (g) -118.24 -130.18 ± 0.59 kJ/mol 98.9586 ± 0.0024 107-06-2*0 Carbon atom anion C- (g) 589.624 594.771 ± 0.050 kJ/mol 12.01125 ± 0.00080 14337-00-9*0 Chloride Cl- (aq) -166.994 ± 0.023 kJ/mol 35.45325 ± 0.00090 16887-00-6*800 Dioxymethylidyne COO (g) 298.6 299.9 ± 1.5 kJ/mol 44.00950 ± 0.00100 791121-04-5*0 Oxadiazirine O(NN) (g) 352.1 350.3 ± 1.4 kJ/mol 44.01288 ± 0.00033 227934-45-4*0 2-Cyclopropyn-1-ylidene C(CC) (g, triplet) 899.2 906.1 ± 1.5 kJ/mol 36.0321 ± 0.0024 102508-15-6*1 Propynylidyne cation [C(CC)]+ (g) 1948.3 1956.2 ± 2.0 kJ/mol 36.0316 ± 0.0024 154702-35-9*0 Ethylene cation [C2H4]+ (g) 1075.28 1068.07 ± 0.13 kJ/mol 28.0526 ± 0.0016 34470-02-5*0 Bifluoride [FHF]- (g) -709.1 -713.0 ± 1.8 kJ/mol 39.005295 ± 0.000070 18130-74-0*0 NON NON (g) 544.7 541.5 ± 1.5 kJ/mol 44.01288 ± 0.00033 227934-46-5*0 Iminomethyl anion [HCNH]- (g, trans) 238.9 235.1 ± 1.9 kJ/mol 28.03387 ± 0.00082 90623-30-6*1 Isoformyl anion [COH]- (g, triplet) 267.4 268.0 ± 1.6 kJ/mol 29.01859 ± 0.00086 81747-63-9*2 2-Propynylium [CH2CCH]+ (g) 1193.47 1190.66 ± 0.38 kJ/mol 39.0554 ± 0.0024 21540-27-2*0 2-Cyclopropen-1-ylium-1-yl [C(CHCH)]+ (g) 1382.0 1381.0 ± 1.2 kJ/mol 38.0474 ± 0.0024 85398-75-0*0 Propynylidene HCCCH (g, cis singlet) 597.6 599.3 ± 1.2 kJ/mol 38.0480 ± 0.0024 67152-18-5*3 Propenediylidene CHCHC (g) 796.2 797.4 ± 1.3 kJ/mol 38.0480 ± 0.0024 60731-11-5*0 Dioxygen anion [O2]- (g) -43.38 -42.74 ± 0.17 kJ/mol 31.99935 ± 0.00060 11062-77-4*0 Trifluoromethide [CF3]- (g) -637.7 -639.6 ± 1.6 kJ/mol 69.00646 ± 0.00080 54128-17-5*0 Hydrogen fluoride HF (aq, 22 H2O) -321.07 ± 0.17 kJ/mol 20.006343 ± 0.000070 7664-39-3*902 Cyclopentene CH2(CH2CHCHCH2) (g) 58.12 33.85 ± 0.45 kJ/mol 68.1170 ± 0.0040 142-29-0*0 Ethyloxoniumyl [CH3CH2OH]+ (g) 784.1 766.9 ± 1.5 kJ/mol 46.0679 ± 0.0017 34480-55-2*0 1-Hydroxyethylium [CH3CHOH]+ (g) 609.14 594.72 ± 0.39 kJ/mol 45.0600 ± 0.0017 18682-96-7*0 Acetaldehyde cation [CH3CHO]+ (g) 832.02 822.04 ± 0.29 kJ/mol 44.0520 ± 0.0017 36505-03-0*0 Oxiranylium [CH2(CHO)]+ (g, triplet) 1233.7 1226.7 ± 1.8 kJ/mol 43.0441 ± 0.0016 57789-76-1*1 Oxiranyl anion [CH2(CHO)]- (g) 121.4 113.3 ± 1.6 kJ/mol 43.0452 ± 0.0016 72722-59-9*0 Dibromine monoxide BrOBr (g) 120.9 104.4 ± 1.3 kJ/mol 175.8074 ± 0.0020 21308-80-5*0 Fluorochlorate [ClF]- (g) -255.99 -255.39 ± 0.80 kJ/mol 54.45165 ± 0.00090 12272-56-9*0 Ethynol anion [HCCO]- (g) -48.62 -47.37 ± 0.87 kJ/mol 41.0293 ± 0.0016 64066-01-9*0 Dicarbon monoxide anion [CCO]- (g) 153.8 157.5 ± 1.2 kJ/mol 40.0213 ± 0.0016 87191-88-6*0 Dicarbon monoxide cation [CCO]+ (g) 1433.5 1438.5 ± 1.8 kJ/mol 40.0203 ± 0.0016 12287-08-0*0 Hydroxyimidogen NOH (g) 217.45 214.57 ± 0.87 kJ/mol 31.01408 ± 0.00032 35337-59-8*0 COC vdW (CO)(C) (g, singlet) 727.2 735.5 ± 1.7 kJ/mol 40.0208 ± 0.0016 *12071-24-8*2 C=O-C cation [COC]+ (g, doublet) 1576.2 1583.3 ± 2.3 kJ/mol 40.0203 ± 0.0016 83483-98-1*1 C=O=C anion [COC]- (g) 551.0 554.7 ± 2.1 kJ/mol 40.0213 ± 0.0016 *87191-88-6*0 Aminylium [NH2]+ (g) 1266.55 1264.47 ± 0.12 kJ/mol 16.02207 ± 0.00016 15194-15-7*0 Formic acid cation [HC(O)OH]+ (g, anti) 723.8 716.7 ± 1.1 kJ/mol 46.0248 ± 0.0010 50614-05-6*2 Formic acid anion [HC(O)OH]- (g, syn) -255.6 -261.8 ± 1.7 kJ/mol 46.0259 ± 0.0010 19066-82-1*1 Nitrous acid HONO (g, cis) -71.37 -77.72 ± 0.29 kJ/mol 47.01348 ± 0.00061 7782-77-6*2 Peroxyhypochlorous acid HOOCl (g) 3.86 -1.42 ± 0.99 kJ/mol 68.4594 ± 0.0011 67952-07-2*0 OH-CO vdW complex (OH)(CO) (g, vdW) -80.30 -77.41 ± 0.96 kJ/mol 45.0174 ± 0.0010 *2564-85-4*100 CO-HO vdW complex (CO)(HO) (g, vdW) -77.6 -73.6 ± 1.8 kJ/mol 45.0174 ± 0.0010 *2564-84-3*100 H-CO2 vdW complex (H)(CO2) (g, vdW) -179.3 -178.3 ± 2.2 kJ/mol 45.0174 ± 0.0010 *2564-83-2*100 Azidonitrene NNNN (g, Cs) 692.0 687.4 ± 1.4 kJ/mol 56.02696 ± 0.00028 147363-92-6*2 Isocyanic acid cation [HNCO]+ (g) 1003.03 1000.37 ± 0.51 kJ/mol 43.02423 ± 0.00086 444010-28-0*0 Isofulminic acid cation [HCNO]+ (g) 1215.8 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 Acetyl chloride CH3C(O)Cl (l) -272.21 ± 0.33 kJ/mol 78.4973 ± 0.0019 75-36-5*500 Chlorosyl ion [ClO]+ (g) 1150.69 1150.53 ± 0.66 kJ/mol 51.45155 ± 0.00095 12301-79-0*0 (Formyloxy)methyl HC(O)OCH2 (g, syn) -148.7 -156.8 ± 1.5 kJ/mol 59.0440 ± 0.0017 3122-12-1*1 Glyoxal (CHO)2 (g, trans) -206.99 -212.63 ± 0.52 kJ/mol 58.0361 ± 0.0017 107-22-2*1 Diazoethenylidene NNCC (g) 657.0 659.6 ± 3.0 kJ/mol 52.0349 ± 0.0016 130760-10-0*0 Isocyanomethylidyne CNC (g) 671.3 675.7 ± 3.6 kJ/mol 38.0281 ± 0.0016 53590-27-5*0 Diazomethyl HCNN (g) 472.8 470.2 ± 2.0 kJ/mol 41.03212 ± 0.00082 20813-32-5*0 Isocyanoamidogen HNNC (g) 492.7 490.7 ± 2.0 kJ/mol 41.03212 ± 0.00082 947408-73-3*0 Tetrachloromethane CCl4 (l) -109.53 -128.94 ± 0.65 kJ/mol 153.8215 ± 0.0037 56-23-5*500 Dioxygenyl ion monohydrate [(H2O)(O2)]+ (g) 828.6 821.5 ± 1.9 kJ/mol 50.01353 ± 0.00091 11083-61-7*0 Chloroform CCl3H (l) -133.87 ± 0.63 kJ/mol 119.3767 ± 0.0028 67-66-3*590