Selected ATcT [1, 2] enthalpy of formation based on version 1.122b of the Thermochemical Network [3] This version of ATcT results was generated from an expansion of version 1.122 [4][5] to include the best possible isomerization of HCN and HNC [6].
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Species Name |
Formula |
Image |
ΔfH°(0 K) |
ΔfH°(298.15 K) |
Uncertainty |
Units |
Relative Molecular Mass |
ATcT ID |
Methyl bromide | CH3Br (g) | | -20.36 | -35.76 | ± 0.27 | kJ/mol | 94.9385 ± 0.0013 | 74-83-9*0 |
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Representative Geometry of CH3Br (g) |
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spin ON spin OFF |
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Top contributors to the provenance of ΔfH° of CH3Br (g)The 20 contributors listed below account only for 46.7% of the provenance of ΔfH° of CH3Br (g). A total of 320 contributors would be needed to account for 90% of the provenance.
Please note: The list is limited to 20 most important contributors or, if less, a number sufficient to account for 90% of the provenance. The Reference acts as a further link to the relevant references and notes for the measurement. The Measured Quantity is normaly given in the original units; in cases where we have reinterpreted the original measurement, the listed value may differ from that given by the authors. The quoted uncertainty is the a priori uncertainty used as input when constructing the initial Thermochemical Network, and corresponds either to the value proposed by the original authors or to our estimate; if an additional multiplier is given in parentheses immediately after the prior uncertainty, it corresponds to the factor by which the prior uncertainty needed to be multiplied during the ATcT analysis in order to make that particular measurement consistent with the prevailing knowledge contained in the Thermochemical Network.
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Contribution (%) | TN ID | Reaction | Measured Quantity | Reference | 9.5 | 3405.1 | CH3Br (g) → [CH3]+ (g) + Br (g)  | ΔrH°(0 K) = 12.834 ± 0.002 (×4.088) eV | Song 2001 | 7.9 | 3388.1 | CH3Cl (g) + 3/2 O2 (g) → CO2 (g) + H2O (cr,l) + HCl (aq, 600 H2O)  | ΔrH°(298.15 K) = -764.00 ± 0.50 (×1.414) kJ/mol | Fletcher 1971 | 2.9 | 752.2 | Br2 (cr,l) → Br2 (g)  | ΔrH°(298.15 K) = 7.386 ± 0.027 kcal/mol | Hildenbrand 1958 | 2.4 | 3424.1 | 2 CH3Br (l) + H2 (g) → 2 CH4 (g) + Br2 (cr,l)  | ΔrH°(298.15 K) = -6.60 ± 0.60 (×1.297) kcal/mol | Adams 1966, as quoted by Cox 1970 | 2.3 | 3420.4 | 4 CH3Br (g) → CBr4 (g) + 3 CH4 (g)  | ΔrH°(0 K) = 2.77 ± 1.0 kcal/mol | Ruscic G4 | 2.2 | 3407.3 | CH3Br (g) + HBr (g) → Br2 (g) + CH4 (g)  | ΔrG°(712.2 K) = 35.8 ± 1.6 (×1.242) kJ/mol | Ferguson 1973, 3rd Law | 2.0 | 3408.1 | CH3Br (g) + H2 (g) → CH4 (g) + HBr (g)  | ΔrH°(523.15 K) = -18.062 ± 0.321 kcal/mol | Fowell 1965 | 1.9 | 3420.3 | 4 CH3Br (g) → CBr4 (g) + 3 CH4 (g)  | ΔrH°(0 K) = 2.69 ± 1.1 kcal/mol | Ruscic G3X | 1.7 | 3392.10 | CH3Cl (g) + H (g) → CH4 (g) + Cl (g)  | ΔrH°(0 K) = -7296 ± 100 (×1.215) cm-1 | Czako 2012 | 1.7 | 1642.1 | 2 H2 (g) + C (graphite) → CH4 (g)  | ΔrG°(1165 K) = 37.521 ± 0.068 kJ/mol | Smith 1946, note COf, 3rd Law | 1.5 | 3405.3 | CH3Br (g) → [CH3]+ (g) + Br (g)  | ΔrH°(0 K) = 12.82 ± 0.02 eV | Traeger 1981, AE corr, note unc2 | 1.5 | 3421.2 | 4 CH3Br (g) + CF4 (g) → 4 CH3F (g) + CBr4 (g)  | ΔrH°(0 K) = 54.31 ± 1.0 kcal/mol | Ruscic G4 | 1.4 | 3385.5 | CH3Cl (g) → C (g) + 3 H (g) + Cl (g)  | ΔrH°(0 K) = 371.34 ± 0.4 kcal/mol | Feller 2008 | 1.2 | 3421.1 | 4 CH3Br (g) + CF4 (g) → 4 CH3F (g) + CBr4 (g)  | ΔrH°(0 K) = 54.25 ± 1.1 kcal/mol | Ruscic G3X | 1.1 | 800.1 | Cl2 (g) + 2 Br- (aq) → Br2 (cr,l) + 2 Cl- (aq)  | ΔrH°(298.15 K) = -91.29 ± 0.40 (×2.768) kJ/mol | Johnson 1963, as quoted by CODATA Key Vals | 1.1 | 800.2 | Cl2 (g) + 2 Br- (aq) → Br2 (cr,l) + 2 Cl- (aq)  | ΔrH°(298.15 K) = -91.29 ± 0.80 (×1.384) kJ/mol | Sunner 1964, as quoted by CODATA Key Vals | 1.0 | 3613.1 | 3 CH3Cl (g) → CCl3H (g) + 2 CH4 (g)  | ΔrH°(0 K) = -2.71 ± 1.2 kcal/mol | Ruscic G3B3 | 1.0 | 3613.2 | 3 CH3Cl (g) → CCl3H (g) + 2 CH4 (g)  | ΔrH°(0 K) = -3.16 ± 1.2 (×1.022) kcal/mol | Ruscic G3 | 0.9 | 803.1 | [HBr]+ (g) → H (g) + Br+ (g)  | ΔrH°(0 K) = 31394.5 ± 20 (×2.229) cm-1 | Haugh 1971, Norling 1935 | 0.7 | 3614.2 | 3 CH3Br (g) → CBr3H (g) + 2 CH4 (g)  | ΔrH°(0 K) = 0.24 ± 1.2 kcal/mol | Ruscic G3B3 |
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Top 10 species with enthalpies of formation correlated to the ΔfH° of CH3Br (g) |
Please note: The correlation coefficients are obtained by renormalizing the off-diagonal elements of the covariance matrix by the corresponding variances. The correlation coefficient is a number from -1 to 1, with 1 representing perfectly correlated species, -1 representing perfectly anti-correlated species, and 0 representing perfectly uncorrelated species.
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Correlation Coefficent (%) | Species Name | Formula | Image | ΔfH°(0 K) | ΔfH°(298.15 K) | Uncertainty | Units | Relative Molecular Mass | ATcT ID | 98.5 | Methyl bromide cation | [CH3Br]+ (g) | | 996.75 | 981.84 | ± 0.27 | kJ/mol | 94.9380 ± 0.0013 | 12538-70-4*0 | 97.3 | Methyl bromide | CH3Br (l) | | -56.08 | -59.10 | ± 0.27 | kJ/mol | 94.9385 ± 0.0013 | 74-83-9*590 | 81.7 | Methyl chloride | CH3Cl (g) | | -74.25 | -82.18 | ± 0.25 | kJ/mol | 50.4872 ± 0.0012 | 74-87-3*0 | 81.3 | Methyl chloride cation | [CH3Cl]+ (g) | | 1015.03 | 1007.58 | ± 0.25 | kJ/mol | 50.4867 ± 0.0012 | 12538-71-5*0 | 81.0 | Methyl chloride | CH3Cl (l) | | -106.05 | -102.08 | ± 0.25 | kJ/mol | 50.4872 ± 0.0012 | 74-87-3*590 | 39.1 | Hydrogen bromide | HBr (g) | | -27.81 | -35.66 | ± 0.16 | kJ/mol | 80.9119 ± 0.0010 | 10035-10-6*0 | 39.1 | Bromoniumyl | [HBr]+ (g) | | 1097.86 | 1090.01 | ± 0.16 | kJ/mol | 80.9114 ± 0.0010 | 12258-64-9*0 | 37.3 | Hydrogen bromide | HBr (aq, 2570 H2O) | | | -120.54 | ± 0.16 | kJ/mol | 80.9119 ± 0.0010 | 10035-10-6*952 | 37.3 | Hydrogen bromide | HBr (aq, 2000 H2O) | | | -120.51 | ± 0.16 | kJ/mol | 80.9119 ± 0.0010 | 10035-10-6*841 | 37.3 | Hydrogen bromide | HBr (aq, 3000 H2O) | | | -120.56 | ± 0.16 | kJ/mol | 80.9119 ± 0.0010 | 10035-10-6*842 |
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Most Influential reactions involving CH3Br (g)Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.
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References
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1
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B. Ruscic, R. E. Pinzon, M. L. Morton, G. von Laszewski, S. Bittner, S. G. Nijsure, K. A. Amin, M. Minkoff, and A. F. Wagner,
Introduction to Active Thermochemical Tables: Several "Key" Enthalpies of Formation Revisited.
J. Phys. Chem. A 108, 9979-9997 (2004)
[DOI: 10.1021/jp047912y]
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2
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B. Ruscic, R. E. Pinzon, G. von Laszewski, D. Kodeboyina, A. Burcat, D. Leahy, D. Montoya, and A. F. Wagner,
Active Thermochemical Tables: Thermochemistry for the 21st Century.
J. Phys. Conf. Ser. 16, 561-570 (2005)
[DOI: 10.1088/1742-6596/16/1/078]
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3
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B. Ruscic and D. H. Bross, Active Thermochemical Tables (ATcT) values based on ver. 1.122b of the Thermochemical Network (2016); available at ATcT.anl.gov |
4
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B. Ruscic,
Active Thermochemical Tables: Sequential Bond Dissociation Enthalpies of Methane, Ethane, and Methanol and the Related Thermochemistry.
J. Phys. Chem. A 119, 7810-7837 (2015)
[DOI: 10.1021/acs.jpca.5b01346]
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5
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S. J. Klippenstein, L. B. Harding, and B. Ruscic,
Ab initio Computations and Active Thermochemical Tables Hand in Hand: Heats of Formation of Core Combustion Species.
J. Phys. Chem. A 121, 6580-6602 (2017)
[DOI: 10.1021/acs.jpca.7b05945]
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6
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T. L. Nguyen, J. H. Baraban, B. Ruscic, and J. F. Stanton,
On the HCN – HNC Energy Difference.
J. Phys. Chem. A 119, 10929-10934 (2015)
[DOI: 10.1021/acs.jpca.5b08406]
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7
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B. Ruscic,
Uncertainty Quantification in Thermochemistry, Benchmarking Electronic Structure Computations, and Active Thermochemical Tables.
Int. J. Quantum Chem. 114, 1097-1101 (2014)
[DOI: 10.1002/qua.24605]
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Formula
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The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.
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Uncertainties
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The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [7]).
Note that an uncertainty of ± 0.000 kJ/mol indicates that the estimated uncertainty is < ± 0.0005 kJ/mol.
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Website Functionality Credits
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The reorganization of the website was developed and implemented by David H. Bross (ANL).
The find function is based on the complete Species Dictionary entries for the appropriate version of the ATcT TN.
The molecule images are rendered by Indigo-depict.
The XYZ renderings are based on Jmol: an open-source Java viewer for chemical structures in 3D. http://www.jmol.org/.
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Acknowledgement
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This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Contract No. DE-AC02-06CH11357.
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