Selected ATcT [1, 2] enthalpy of formation based on version 1.172 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.156 to include species relevant to a study of photodissociation of formamide[4].

Methane

Formula: CH4 (g)
CAS RN: 74-82-8
ATcT ID: 74-82-8*0
SMILES: C
InChI: InChI=1S/CH4/h1H4
InChIKey: VNWKTOKETHGBQD-UHFFFAOYSA-N
Hills Formula: C1H4

2D Image:

C
Aliases: CH4; Methane; Methyl hydride; Marsh gas
Relative Molecular Mass: 16.04246 ± 0.00085

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
-66.547-74.516± 0.043kJ/mol

3D Image of CH4 (g)

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Top contributors to the provenance of ΔfH° of CH4 (g)

The 20 contributors listed below account only for 62.6% of the provenance of ΔfH° of CH4 (g).
A total of 363 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.

Contribution
(%)
TN
ID
Reaction Measured Quantity Reference
39.82375.1 H2 (g) C (graphite) → CH4 (g) ΔrG°(1165 K) = 37.521 ± 0.068 kJ/molSmith 1946, note COf, 3rd Law
7.12373.7 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.578 ± 0.078 kJ/molSchley 2010
5.9125.2 1/2 O2 (g) H2 (g) → H2O (cr,l) ΔrH°(298.15 K) = -285.8261 ± 0.040 kJ/molRossini 1939, Rossini 1931, Rossini 1931b, note H2Oa, Rossini 1930
1.12228.7 C (graphite) O2 (g) → CO2 (g) ΔrH°(298.15 K) = -393.464 ± 0.024 kJ/molHawtin 1966, note CO2e
1.12268.11 CO (g) → C (g) O (g) ΔrH°(0 K) = 1071.92 ± 0.10 kJ/molThorpe 2021
0.92373.4 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.61 ± 0.21 kJ/molDale 2002
0.62286.9 C (graphite) CO2 (g) → 2 CO (g) ΔrG°(1165 K) = -33.545 ± 0.058 kJ/molSmith 1946, note COf, 3rd Law
0.62373.8 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.482 ± 0.260 kJ/molHaloua 2015
0.62373.6 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.44 ± 0.26 kJ/molGOMB Ref Calorimeter, Alexandrov 2002
0.52278.2 CO (g) → C+ (g) O (g) ΔrH°(0 K) = 22.3713 ± 0.0015 eVNg 2007
0.42228.4 C (graphite) O2 (g) → CO2 (g) ΔrH°(298.15 K) = -393.462 ± 0.038 kJ/molLewis 1965, note CO2d
0.42228.5 C (graphite) O2 (g) → CO2 (g) ΔrH°(298.15 K) = -393.468 ± 0.038 kJ/molFraser 1952, note CO2f
0.42388.12 CH3 (g) → C (g) + 3 H (g) ΔrH°(0 K) = 289.11 ± 0.10 kcal/molFeller 2016, note unc2
0.4115.11 H2O (g) → O (g) + 2 H (g) ΔrH°(0 K) = 917.80 ± 0.15 kJ/molThorpe 2021
0.3157.1 OH (g) → [OH]+ (g) ΔrH°(0 K) = 104989 ± 5 (×2.378) cm-1Wiedmann 1992, note unc
0.32373.1 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(303.15 K) = -889.849 ± 0.350 kJ/molRossini 1931a, Rossini 1931b, Prosen 1945, Rossini 1940, note CH4
0.32373.5 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.43 ± 0.35 kJ/molAlexandrov 2002a, Alexandrov 2002
0.33834.1 CH4 (g) → CH3CHCCH2 (g) + 5 H2 (g) ΔrH°(0 K) = 442.41 ± 2.00 kJ/molKlippenstein 2017
0.32430.1 CH3 (g) → CH2 (g, triplet) H (g) ΔrH°(0 K) = 109.26 ± 0.08 kcal/molFeller 2016, est unc, note unc2
0.3167.6 H2O (g) → [OH]+ (g) H (g) ΔrH°(0 K) = 18.1183 ± 0.0015 (×1.067) eVBodi 2014

Top 10 species with enthalpies of formation correlated to the ΔfH° of CH4 (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.


Correlation
Coefficent
(%)
Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass
ATcT ID
96.1 Methylium[CH3]+ (g)[CH3+]1099.3491095.405± 0.045kJ/mol15.03397 ±
0.00083
14531-53-4*0
85.1 MethylCH3 (g)[CH3]149.876146.475± 0.049kJ/mol15.03452 ±
0.00083
2229-07-4*0
76.9 Methane cation[CH4]+ (g)[CH4+]1150.6831144.300± 0.057kJ/mol16.04191 ±
0.00085
20741-88-2*0
70.7 MethaneCH4 (aq, undissoc)C-87.699± 0.061kJ/mol16.04246 ±
0.00085
74-82-8*1000
45.4 Carbonic acidC(O)(OH)2 (aq, undissoc)OC(=O)O-698.673± 0.028kJ/mol62.0248 ±
0.0012
463-79-6*1000
44.8 WaterH2O (l, eq.press.)O-285.806± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*589
44.8 WaterH2O (l)O-285.804± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*590
44.8 Oxonium[H3O]+ (aq)[OH3+]-285.804± 0.022kJ/mol19.02267 ±
0.00037
13968-08-6*800
44.8 WaterH2O (cr,l)O-286.276-285.804± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*500
44.8 WaterH2O (cr, l, eq.press.)O-286.278-285.806± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*499

Most Influential reactions involving CH4 (g)

Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.

Influence
Coefficient
TN
ID
Reaction Measured Quantity Reference
0.9882369.1 CH4 (g) → [CH4]+ (g) ΔrH°(0 K) = 101752.2 ± 3.0 cm-1Worner 2007, note unc
0.9572398.1 CH4 (g) → [CH3]+ (g) H (g) ΔrH°(0 K) = 14.32271 ± 0.00013 eVChang 2017
0.7362376.1 CH4 (g) → CH4 (aq, undissoc) ΔrG°(298.15 K) = 16.300 ± 0.05 kJ/molClever 1987
0.7262371.3 [CH4]- (g) → CH4 (g) ΔrH°(0 K) = -0.997 ± 0.061 eVRuscic G4
0.6578964.1 CH4 (g) → HCCCCCH (g, triplet) + 9 H2 (g) ΔrH°(0 K) = 1059.82 ± 2.00 kJ/molKlippenstein 2017
0.5215233.1 CH4 (g) + 2 H2O (g) → CH3OCO (g, syn-staggered) + 9/2 H2 (g) ΔrH°(0 K) = 459.60 ± 2.00 kJ/molKlippenstein 2017
0.5114508.1 CH4 (g) H2O (g) → HCC(O)H (g, syn-triplet) + 4 H2 (g) ΔrH°(0 K) = 633.00 ± 1.5 kJ/molKlippenstein 2017
0.3992375.1 H2 (g) C (graphite) → CH4 (g) ΔrG°(1165 K) = 37.521 ± 0.068 kJ/molSmith 1946, note COf, 3rd Law
0.3912856.6 HCCNH (g) CH4 (g) → CH3NH (g) HCCH (g) ΔrH°(0 K) = 87.84 ± 1.5 kJ/molKlippenstein 2017
0.3487826.1 CH4 (g) + 2 H2O (g) → OCCO (g) + 6 H2 (g) ΔrH°(0 K) = 625.09 ± 2.00 kJ/molKlippenstein 2017
0.3197445.1 CH4 (g) H2O (g) → CH2C(OH)CH2 (g) + 9/2 H2 (g) ΔrH°(0 K) = 442.37 ± 2.00 kJ/molKlippenstein 2017
0.3192373.7 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.578 ± 0.078 kJ/molSchley 2010
0.3086432.6 CH4 (g) CCl4 (g) → 2 CH2Cl2 (g) ΔrH°(0 K) = -4.40 ± 0.25 kcal/molKarton 2017, Karton 2011, Karton 2007, Karton 2006
0.2806636.2 HCCH (g) + 2 CH3Br (g) → BrCCBr (g) + 2 CH4 (g) ΔrH°(0 K) = 2.34 ± 1.0 kcal/molRuscic G4
0.2736596.11 CH2CHF (g) CH4 (g) → CH2CH2 (g) CH3F (g) ΔrH°(0 K) = 8.36 ± 0.20 kcal/molKarton 2011
0.2666194.8 HCCCl (g) CH3Cl (g) → ClCCCl (g) CH4 (g) ΔrH°(0 K) = 2.93 ± 0.25 kcal/molKarton 2017, Karton 2011, Karton 2007, Karton 2006
0.2626245.6 CH3Cl (g) → CCl4 (g) + 3 CH4 (g) ΔrH°(0 K) = 2.52 ± 0.30 kcal/molKarton 2017
0.2522383.5 [CH5]+ (g) CO2 (g) → [HOCO]+ (g) CH4 (g) ΔrG°(296 K) = 7.92 ± 0.20 kJ/molBohme 1973a, 3rd Law, note unc
0.2528588.7 SiH3SiH3 (g) + 2 CH4 (g) → CH3CH3 (g) + 2 SiH4 (g) ΔrH°(0 K) = 13.99 ± 0.2 kcal/molKarton 2011, Karton 2007b
0.2516642.12 HCCF (g) CH3F (g) → FCCF (g) CH4 (g) ΔrH°(0 K) = 14.03 ± 0.20 kcal/molKarton 2011


References
1   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]
2   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]
3   B. Ruscic and D. H. Bross,
Active Thermochemical Tables (ATcT) values based on ver. 1.172 of the Thermochemical Network (2024); available at ATcT.anl.gov
4   K. L. Caster, N. A. Seifert, B. Ruscic, A. W. Jasper, and K. Prozument,
Dynamics of HCN, NHC, and HNCO Formation in the 193 nm Photodissociation of Formamide
J. Phys. Chem. A (in press) (2024) [DOI: 10.1021/acs.jpca.4c02232]
5   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]
6   B. Ruscic and D. H. Bross,
Thermochemistry
Computer Aided Chem. Eng. 45, 3-114 (2019) [DOI: 10.1016/B978-0-444-64087-1.00001-2]

Formula
The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.

Uncertainties
The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [5] and Ruscic and Bross[6]).
Note that an uncertainty of ± 0.000 kJ/mol indicates that the estimated uncertainty is < ± 0.0005 kJ/mol.

Website Functionality Credits
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/.

Acknowledgement
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.