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].

Methanide

Formula: [CH3]- (g)

CAS RN: 15194-58-8

ATcT ID: 15194-58-8*0

SMILES: [CH3-]

InChI: InChI=1S/CH3/h1H3/q-1

InChIKey: LGRLWUINFJPLSH-UHFFFAOYSA-N

Hills Formula: C1H3-

2D Image:

Aliases: [CH3]-; Methanide; Methide; Methyl carbanion; Methyl anion; Methyl ion (1-); Methide anion

Relative Molecular Mass: 15.03507 ± 0.00083

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
141.15	137.71	± 0.24	kJ/mol

3D Image of [CH3]- (g)

spin ON spin OFF

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

The 5 contributors listed below account for 92.2% of the provenance of Δ_fH° of [CH3]- (g).

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
62.7	2393.1	[CH3]- (g) → CH3 (g)	Δ_rH°(0 K) = 0.093 ± 0.003 eV	Oliveira 2015
8.8	2393.14	[CH3]- (g) → CH3 (g)	Δ_rH°(0 K) = 0.093 ± 0.008 eV	Feller 2016, note unc2
7.8	2397.1	[CH3]- (g) → C- (g) + 3 H (g)	Δ_rH°(0 K) = 262.0 ± 0.2 kcal/mol	Feller 2016, note unc2
7.1	2435.1	[CH3]- (g) → [CH2]- (g) + H (g)	Δ_rH°(0 K) = 96.3 ± 0.2 kcal/mol	Feller 2016, est unc, note unc2
5.6	2393.13	[CH3]- (g) → CH3 (g)	Δ_rH°(0 K) = 0.094 ± 0.010 eV	Oliveira 2015

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
18.4	Methyl	CH3 (g)	149.876	146.476	± 0.049	kJ/mol	15.03452 ± 0.00083	2229-07-4*0
16.5	Methylium	[CH3]+ (g)	1099.349	1095.405	± 0.045	kJ/mol	15.03397 ± 0.00083	14531-53-4*0
15.9	Methane	CH4 (g)	-66.547	-74.516	± 0.043	kJ/mol	16.04246 ± 0.00085	74-82-8*0
12.2	Methane cation	[CH4]+ (g)	1150.683	1144.300	± 0.057	kJ/mol	16.04191 ± 0.00085	20741-88-2*0
11.3	Methane	CH4 (aq, undissoc)		-87.699	± 0.061	kJ/mol	16.04246 ± 0.00085	74-82-8*1000
8.3	Carbon	C (g, singlet)	833.312	838.459	± 0.039	kJ/mol	12.01070 ± 0.00080	7440-44-0*2
8.3	Carbon cation	C+ (g)	1797.834	1803.432	± 0.039	kJ/mol	12.01015 ± 0.00080	14067-05-1*0
8.3	Carbon	C (g, triplet)	711.381	716.866	± 0.039	kJ/mol	12.01070 ± 0.00080	7440-44-0*1
8.3	Carbon	C (g)	711.381	716.866	± 0.039	kJ/mol	12.01070 ± 0.00080	7440-44-0*0
8.3	Carbon	C (g, quintuplet)	1114.944	1120.091	± 0.039	kJ/mol	12.01070 ± 0.00080	7440-44-0*3

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
0.116	2435.1	[CH3]- (g) → [CH2]- (g) + H (g)	Δ_rH°(0 K) = 96.3 ± 0.2 kcal/mol	Feller 2016, est unc, note unc2
0.092	2393.14	[CH3]- (g) → CH3 (g)	Δ_rH°(0 K) = 0.093 ± 0.008 eV	Feller 2016, note unc2
0.081	2397.1	[CH3]- (g) → C- (g) + 3 H (g)	Δ_rH°(0 K) = 262.0 ± 0.2 kcal/mol	Feller 2016, note unc2
0.073	3274.1	[CH3CH2CH2]- (g) + CH4 (g) → CH3CH2CH3 (g) + [CH3]- (g)	Δ_rH°(298.15 K) = 1.0 ± 1.0 kcal/mol	DePuy 1989
0.071	3440.6	CH2(CH2CH2) (g) + [CH3]- (g) → [CH(CH2CH2)]- (g) + CH4 (g)	Δ_rH°(0 K) = -4.16 ± 0.8 (×1.215) kcal/mol	Ruscic W1RO
0.059	2393.13	[CH3]- (g) → CH3 (g)	Δ_rH°(0 K) = 0.094 ± 0.010 eV	Oliveira 2015
0.044	2511.1	[CH3CH2]- (g) + CH4 (g) → [CH3]- (g) + CH3CH3 (g)	Δ_rH°(298.15 K) = -3.5 ± 1.0 kcal/mol	DePuy 1989
0.022	3440.5	CH2(CH2CH2) (g) + [CH3]- (g) → [CH(CH2CH2)]- (g) + CH4 (g)	Δ_rH°(0 K) = -4.89 ± 1.0 (×1.719) kcal/mol	Ruscic CBS-n
0.017	2511.5	[CH3CH2]- (g) + CH4 (g) → [CH3]- (g) + CH3CH3 (g)	Δ_rH°(0 K) = -2.30 ± 0.9 (×1.756) kcal/mol	Ruscic W1RO
0.016	3440.1	CH2(CH2CH2) (g) + [CH3]- (g) → [CH(CH2CH2)]- (g) + CH4 (g)	Δ_rH°(298.15 K) = -5.1 ± 2. kcal/mol	DePuy 1989, DePuy 1984, note unc
0.015	2511.4	[CH3CH2]- (g) + CH4 (g) → [CH3]- (g) + CH3CH3 (g)	Δ_rH°(0 K) = -2.19 ± 1.0 (×1.682) kcal/mol	Ruscic CBS-n
0.015	2512.5	[CH3CH2]- (g) + CH3 (g) → CH3CH2 (g) + [CH3]- (g)	Δ_rH°(0 K) = -0.265 ± 0.039 (×1.915) eV	Ruscic W1RO
0.015	2393.15	[CH3]- (g) → CH3 (g)	Δ_rH°(0 K) = 1.64 ± 0.3 (×1.509) kcal/mol	Dixon 1997
0.012	2512.4	[CH3CH2]- (g) + CH3 (g) → CH3CH2 (g) + [CH3]- (g)	Δ_rH°(0 K) = -0.255 ± 0.043 (×1.957) eV	Ruscic CBS-n
0.009	3440.4	CH2(CH2CH2) (g) + [CH3]- (g) → [CH(CH2CH2)]- (g) + CH4 (g)	Δ_rH°(0 K) = -5.82 ± 1.3 (×2.044) kcal/mol	Ruscic CBS-n
0.007	3440.3	CH2(CH2CH2) (g) + [CH3]- (g) → [CH(CH2CH2)]- (g) + CH4 (g)	Δ_rH°(0 K) = -6.10 ± 1.0 (×2.954) kcal/mol	Ruscic G4
0.007	2512.3	[CH3CH2]- (g) + CH3 (g) → CH3CH2 (g) + [CH3]- (g)	Δ_rH°(0 K) = -0.232 ± 0.056 (×1.915) eV	Ruscic CBS-n
0.006	2512.2	[CH3CH2]- (g) + CH3 (g) → CH3CH2 (g) + [CH3]- (g)	Δ_rH°(0 K) = -0.229 ± 0.043 (×2.594) eV	Ruscic G4
0.006	2511.3	[CH3CH2]- (g) + CH4 (g) → [CH3]- (g) + CH3CH3 (g)	Δ_rH°(0 K) = -1.32 ± 1.0 (×2.538) 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.