Selected ATcT [1, 2] enthalpy of formation based on version 1.176 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.172 to include species related to Criegee intermediates that are involved in several ongoing studies[4].

Methyl

Formula: CH3 (g)

CAS RN: 2229-07-4

ATcT ID: 2229-07-4*0

SMILES: [CH3]

InChI: InChI=1S/CH3/h1H3

InChIKey: WCYWZMWISLQXQU-UHFFFAOYSA-N

Hills Formula: C1H3

2D Image:

Aliases: CH3; Methyl; Methyl radical

Relative Molecular Mass: 15.03452 ± 0.00083

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
149.876	146.476	± 0.049	kJ/mol

3D Image of CH3 (g)

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Top contributors to the provenance of Δ_fH° of CH3 (g)

The 20 contributors listed below account only for 67.0% of the provenance of Δ_fH° of CH3 (g).
A total of 303 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
28.8	2375.1	2 H2 (g) + C (graphite) → CH4 (g)	Δ_rG°(1165 K) = 37.521 ± 0.068 kJ/mol	Smith 1946, note COf, 3rd Law
7.5	2391.2	CH3 (g) → [CH3]+ (g)	Δ_rH°(0 K) = 79369.9 ± 3 cm-1	Schulenburg 2006, note CH3
7.5	2391.1	CH3 (g) → [CH3]+ (g)	Δ_rH°(0 K) = 79370.4 ± 3 cm-1	Schulenburg 2006, note CH3
4.9	2373.7	CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -890.578 ± 0.078 kJ/mol	Schley 2010
4.6	2398.1	CH4 (g) → [CH3]+ (g) + H (g)	Δ_rH°(0 K) = 14.32271 ± 0.00013 eV	Chang 2017
4.4	125.2	1/2 O2 (g) + H2 (g) → H2O (cr,l)	Δ_rH°(298.15 K) = -285.8261 ± 0.040 kJ/mol	Rossini 1939, Rossini 1931, Rossini 1931b, note H2Oa, Rossini 1930
1.4	2391.4	CH3 (g) → [CH3]+ (g)	Δ_rH°(0 K) = 79363 ± 3 (×2.278) cm-1	Blush 1993, note CH3
0.9	2268.11	CO (g) → C (g) + O (g)	Δ_rH°(0 K) = 1071.92 ± 0.10 kJ/mol	Thorpe 2021
0.9	2228.7	C (graphite) + O2 (g) → CO2 (g)	Δ_rH°(298.15 K) = -393.464 ± 0.024 kJ/mol	Hawtin 1966, note CO2e
0.7	2388.12	CH3 (g) → C (g) + 3 H (g)	Δ_rH°(0 K) = 289.11 ± 0.10 kcal/mol	Feller 2016, note unc2
0.6	2373.4	CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -890.61 ± 0.21 kJ/mol	Dale 2002
0.6	2392.12	CH3 (g) → [CH3]+ (g)	Δ_rH°(0 K) = 226.946 ± 0.029 kcal/mol	Feller 2017a
0.6	2430.1	CH3 (g) → CH2 (g, triplet) + H (g)	Δ_rH°(0 K) = 109.26 ± 0.08 kcal/mol	Feller 2016, est unc, note unc2
0.5	2286.9	C (graphite) + CO2 (g) → 2 CO (g)	Δ_rG°(1165 K) = -33.545 ± 0.058 kJ/mol	Smith 1946, note COf, 3rd Law
0.4	2278.2	CO (g) → C+ (g) + O (g)	Δ_rH°(0 K) = 22.3713 ± 0.0015 eV	Ng 2007
0.4	2373.8	CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -890.482 ± 0.260 kJ/mol	Haloua 2015
0.4	2373.6	CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -890.44 ± 0.26 kJ/mol	GOMB Ref Calorimeter, Alexandrov 2002
0.4	2390.4	CH3 (g) → C (g) + 3 H (g)	Δ_rH°(0 K) = 1209.50 ± 0.56 kJ/mol	Harding 2008
0.3	2228.5	C (graphite) + O2 (g) → CO2 (g)	Δ_rH°(298.15 K) = -393.468 ± 0.038 kJ/mol	Fraser 1952, note CO2f
0.3	2228.4	C (graphite) + O2 (g) → CO2 (g)	Δ_rH°(298.15 K) = -393.462 ± 0.038 kJ/mol	Lewis 1965, note CO2d

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH3 (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	Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units	Relative Molecular Mass	ATcT ID
88.3	Methylium	[CH3]+ (g)	1099.349	1095.405	± 0.045	kJ/mol	15.03397 ± 0.00083	14531-53-4*0
85.1	Methane	CH4 (g)	-66.547	-74.516	± 0.043	kJ/mol	16.04246 ± 0.00085	74-82-8*0
65.4	Methane cation	[CH4]+ (g)	1150.683	1144.300	± 0.057	kJ/mol	16.04191 ± 0.00085	20741-88-2*0
60.2	Methane	CH4 (aq, undissoc)		-87.699	± 0.061	kJ/mol	16.04246 ± 0.00085	74-82-8*1000
39.4	Carbonic acid	C(O)(OH)2 (aq, undissoc)		-698.673	± 0.028	kJ/mol	62.0248 ± 0.0012	463-79-6*1000
38.7	Water	H2O (l, eq.press.)		-285.806	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*589
38.7	Water	H2O (l)		-285.804	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*590
38.7	Oxonium	[H3O]+ (aq)		-285.804	± 0.022	kJ/mol	19.02267 ± 0.00037	13968-08-6*800
38.7	Water	H2O (cr,l)	-286.276	-285.804	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*500
38.7	Water	H2O (cr, l, eq.press.)	-286.278	-285.806	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*499

Most Influential reactions involving CH3 (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
0.655	2393.1	[CH3]- (g) → CH3 (g)	Δ_rH°(0 K) = 0.093 ± 0.003 eV	Oliveira 2015
0.540	8771.1	Si(CH3)4 (g) → [Si(CH3)3]+ (g) + CH3 (g)	Δ_rH°(0 K) = 10.28 ± 0.01 eV	Szepes 1984
0.479	7429.1	CH3C(O)CH3 (g) → [CH3CO]+ (g) + CH3 (g)	Δ_rH°(0 K) = 10.532 ± 0.006 eV	Bodi 2015
0.459	9108.1	CH3CH2NH2 (g) → [CH2NH2]+ (g) + CH3 (g)	Δ_rH°(0 K) = 9.754 ± 0.008 eV	Bodi 2006a
0.411	2391.1	CH3 (g) → [CH3]+ (g)	Δ_rH°(0 K) = 79370.4 ± 3 cm-1	Schulenburg 2006, note CH3
0.411	2391.2	CH3 (g) → [CH3]+ (g)	Δ_rH°(0 K) = 79369.9 ± 3 cm-1	Schulenburg 2006, note CH3
0.255	8763.1	SiI(CH3)3 (g) + CH3 (g) → Si(CH3)4 (g) + I (g)	Δ_rH°(0 K) = -0.41 ± 0.02 eV	Szepes 1984
0.219	8762.1	SiBr(CH3)3 (g) + CH3 (g) → Si(CH3)4 (g) + Br (g)	Δ_rH°(0 K) = 0.42 ± 0.02 eV	Szepes 1984
0.217	4630.6	CH3OO (g) → CH3 (g) + O2 (g)	Δ_rH°(0 K) = 30.40 ± 0.17 kcal/mol	Nguyen 2014a
0.209	7619.5	(CH2C(O)OH)2 (g) + 2 CH3 (g) → 2 CH2C(O)OH (g, syn) + CH3CH3 (g)	Δ_rH°(0 K) = -4.89 ± 0.9 kcal/mol	Ruscic W1RO
0.169	7619.4	(CH2C(O)OH)2 (g) + 2 CH3 (g) → 2 CH2C(O)OH (g, syn) + CH3CH3 (g)	Δ_rH°(0 K) = -4.68 ± 1.0 kcal/mol	Ruscic CBS-n
0.169	7619.2	(CH2C(O)OH)2 (g) + 2 CH3 (g) → 2 CH2C(O)OH (g, syn) + CH3CH3 (g)	Δ_rH°(0 K) = -5.31 ± 1.0 kcal/mol	Ruscic G4
0.163	3744.1	C(CH3)4 (g) → [(CH3)3C]+ (g) + CH3 (g)	Δ_rH°(0 K) = 10.564 ± 0.025 eV	Stevens 2010b
0.156	2682.8	CH2NH2 (g) + CH4 (g) → CH3NH2 (g) + CH3 (g)	Δ_rH°(0 K) = 12.19 ± 0.20 kcal/mol	Karton 2011
0.128	3868.7	CH2CHCCH2 (g) + CH4 (g) → CH2CHCHCH2 (g) + CH3 (g)	Δ_rH°(0 K) = 14.19 ± 2.00 kJ/mol	Klippenstein 2017
0.125	6062.4	CH2Cl (g) + CHCl2 (g) → CCl3 (g) + CH3 (g)	Δ_rH°(0 K) = 3.37 ± 0.9 kcal/mol	Ruscic W1RO
0.117	3868.6	CH2CHCCH2 (g) + CH4 (g) → CH2CHCHCH2 (g) + CH3 (g)	Δ_rH°(0 K) = 3.22 ± 0.50 kcal/mol	Wheeler 2004, est unc
0.111	8443.4	HCCCH2Cl (g) + CH3 (g) → CH2CCH (g) + CH3Cl (g)	Δ_rH°(0 K) = -13.58 ± 0.9 kcal/mol	Ruscic W1RO
0.111	6980.5	C6H5CH (g, triplet) + CH3 (g) → C6H5CH2 (g) + CH2 (g, triplet)	Δ_rH°(0 K) = -0.21 ± 0.85 kcal/mol	Ruscic W1RO
0.106	8437.2	C6H5OO (g) + CH3 (g) → C6H5 (g) + CH3OO (g)	Δ_rH°(0 K) = 16.66 ± 1.0 kcal/mol	Ruscic G4

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 21^st 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. 1.176 of the Thermochemical Network (2024); available at ATcT.anl.gov
4		T. L. Nguyen et al, ongoing studies (2024)
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.