Selected ATcT [1, 2] enthalpy of formation based on version 1.156 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.148 to include species relevant to a recent study of the oxidation of ethylene [4] as well as new measurements that led to refining the thermochemistry of CF and SiF and their cations [5].

Methylidyne

Formula: CH (g)

CAS RN: 3315-37-5

ATcT ID: 3315-37-5*0

SMILES: [CH]

InChI: InChI=1S/CH/h1H

InChIKey: VRLIPUYDFBXWCH-UHFFFAOYSA-N

Hills Formula: C1H1

2D Image:

Aliases: CH; Methylidyne; Methylidyne radical; Methyne radical; Methyne; Carbyne; Hydridocarbon; Carbon hydride; Carbon monohydride

Relative Molecular Mass: 13.01864 ± 0.00080

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
592.990	596.324	± 0.081	kJ/mol

3D Image of CH (g)

spin ON spin OFF

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

The 20 contributors listed below account only for 59.5% of the provenance of Δ_fH° of CH (g).
A total of 302 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
11.8	2422.1	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 27954.0 ± 15 cm-1	Thorpe 2021a, Thorpe 2021
11.8	2422.2	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 27955.6 ± 15 cm-1	Thorpe 2021a
11.7	2425.1	CH (g) → [CH]+ (g)	Δ_rH°(0 K) = 85828.7 ± 15 cm-1	Thorpe 2021a, Thorpe 2021
3.3	2423.12	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 80.01 ± 0.08 kcal/mol	Feller 2014, note unc
3.2	2423.2	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 334.55 ± 0.34 kJ/mol	Csaszar 2002
2.1	2423.11	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 79.94 ± 0.1 kcal/mol	Feller 2008
1.9	2437.8	CH2 (g, triplet) → CH (g) + H (g)	Δ_rH°(0 K) = 418.04 ± 0.35 kJ/mol	Csaszar 2003
1.7	2359.1	2 H2 (g) + C (graphite) → CH4 (g)	Δ_rG°(1165 K) = 37.521 ± 0.068 kJ/mol	Smith 1946, note COf, 3rd Law
1.6	2252.11	CO (g) → C (g) + O (g)	Δ_rH°(0 K) = 1071.92 ± 0.10 (×1.242) kJ/mol	Thorpe 2021
1.2	2262.2	CO (g) → C+ (g) + O (g)	Δ_rH°(0 K) = 22.3713 ± 0.0015 eV	Ng 2007
1.2	2422.6	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 334.49 ± 0.56 kJ/mol	Harding 2008
0.9	2421.12	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 79.95 ± 0.15 kcal/mol	Karton 2007a
0.9	2438.5	CH2 (g, singlet) → CH (g) + H (g)	Δ_rH°(0 K) = 90.97 ± 0.12 kcal/mol	Feller 2014
0.9	2426.13	[CH]- (g) → CH (g)	Δ_rH°(0 K) = 1.215 ± 0.005 eV	Feller 2016, Feller 2016a, note unc3
0.8	6451.11	CF (g) → C (g) + F (g)	Δ_rH°(0 K) = 545.41 ± 0.56 kJ/mol	Harding 2008
0.8	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
0.7	2422.4	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 334.47 ± 0.70 kJ/mol	Harding 2008
0.7	2437.4	CH2 (g, triplet) → CH (g) + H (g)	Δ_rH°(0 K) = 417.96 ± 0.56 kJ/mol	Harding 2008
0.6	2422.5	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 334.48 ± 0.74 kJ/mol	Harding 2008
0.6	2422.3	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 334.68 ± 0.75 kJ/mol	Tajti 2004, est unc

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH (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
100.0	Methylidyne	CH (g, doublet)	592.990	596.324	± 0.081	kJ/mol	13.01864 ± 0.00080	3315-37-5*1
67.0	Fluoromethylidyne	CF (g)	243.19	246.79	± 0.11	kJ/mol	31.00910 ± 0.00080	3889-75-6*0
48.0	Carbon	C (g, quintuplet)	1114.963	1120.109	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*3
48.0	Carbon	C (g, singlet)	833.331	838.477	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*2
48.0	Carbon cation	C+ (g)	1797.853	1803.451	± 0.040	kJ/mol	12.01015 ± 0.00080	14067-05-1*0
48.0	Carbon	C (g, triplet)	711.400	716.885	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*1
48.0	Carbon	C (g)	711.400	716.885	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*0
47.9	Carbon dication	[C]+2 (g)	4150.469	4155.616	± 0.040	kJ/mol	12.00960 ± 0.00080	16092-61-8*0
47.8	Carbon anion	C- (g)	589.624	594.770	± 0.040	kJ/mol	12.01125 ± 0.00080	14337-00-9*0
47.5	Methyliumylidene	[CH]+ (g)	1619.757	1623.100	± 0.041	kJ/mol	13.01809 ± 0.00080	24361-82-8*0

Most Influential reactions involving CH (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
1.000	2430.1	CH (g) → CH (g, doublet)	Δ_rH°(0 K) = 0 ± 0 cm-1	Botterud 1973, Huber 1979
0.238	4331.11	HCCO (g) → CH (g) + CO (g)	Δ_rH°(0 K) = 302.2 ± 1.1 kJ/mol	Szalay 2004
0.194	8386.5	SiF (g, doublet) + CH (g) → SiH (g) + CF (g)	Δ_rH°(0 K) = 19.61 ± 0.25 kcal/mol	Karton 2007b
0.194	2426.13	[CH]- (g) → CH (g)	Δ_rH°(0 K) = 1.215 ± 0.005 eV	Feller 2016, Feller 2016a, note unc3
0.160	5595.10	NCN (g) + H (g) → CH (g) + N2 (g)	Δ_rH°(0 K) = -74.42 ± 1.0 kJ/mol	Harding 2018
0.157	2425.1	CH (g) → [CH]+ (g)	Δ_rH°(0 K) = 85828.7 ± 15 cm-1	Thorpe 2021a, Thorpe 2021
0.156	2422.1	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 27954.0 ± 15 cm-1	Thorpe 2021a, Thorpe 2021
0.156	2422.2	CH (g) → C (g) + H (g)	Δ_rH°(0 K) = 27955.6 ± 15 cm-1	Thorpe 2021a
0.148	6457.6	4 CF (g) + CH4 (g) → 4 CH (g) + CF4 (g)	Δ_rH°(0 K) = 128.62 ± 0.20 kcal/mol	Karton 2007b
0.148	6457.5	4 CF (g) + CH4 (g) → 4 CH (g) + CF4 (g)	Δ_rH°(0 K) = 128.63 ± 0.20 kcal/mol	Karton 2007b
0.148	6457.4	4 CF (g) + CH4 (g) → 4 CH (g) + CF4 (g)	Δ_rH°(0 K) = 128.62 ± 0.20 kcal/mol	Karton 2007b
0.098	5625.9	HNCN (g, doublet) → CH (g) + N2 (g)	Δ_rH°(0 K) = 271.15 ± 2.0 kJ/mol	Klippenstein 2017
0.082	2437.8	CH2 (g, triplet) → CH (g) + H (g)	Δ_rH°(0 K) = 418.04 ± 0.35 kJ/mol	Csaszar 2003
0.082	6458.10	2 CF (g) + H2 (g) → 2 CH (g) + F2 (g)	Δ_rH°(0 K) = 699.43 ± 0.56 kJ/mol	Harding 2008
0.072	6458.7	2 CF (g) + H2 (g) → 2 CH (g) + F2 (g)	Δ_rH°(0 K) = 699.65 ± 0.60 kJ/mol	Tajti 2004, est unc
0.066	6457.3	4 CF (g) + CH4 (g) → 4 CH (g) + CF4 (g)	Δ_rH°(0 K) = 128.58 ± 0.30 kcal/mol	Karton 2007b
0.052	6458.8	2 CF (g) + H2 (g) → 2 CH (g) + F2 (g)	Δ_rH°(0 K) = 699.79 ± 0.70 kJ/mol	Harding 2008
0.051	5695.6	HNNC (g, doublet) → CH (g) + N2 (g)	Δ_rH°(0 K) = 23.68 ± 1.2 kcal/mol	Harding 2008a, est unc
0.047	6458.9	2 CF (g) + H2 (g) → 2 CH (g) + F2 (g)	Δ_rH°(0 K) = 699.72 ± 0.74 kJ/mol	Harding 2008
0.047	5625.1	HNCN (g, doublet) → CH (g) + N2 (g)	Δ_rH°(0 K) = 2.80 ± 0.03 eV	Bise 2001

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. 1.156 of the Thermochemical Network (2024); available at ATcT.anl.gov
4		N. A. Seifert, B. Ruscic, R. Sivaramakrishnan, and K. Prozument, The C2H4O Isomers in the Oxidation of Ethylene J. Mol. Spectrosc. 398, 111847/1-8 (2023) [DOI: 10.1016/j.jms.2023.111847]
5		U. Jacovella, B. Ruscic, N. L. Chen, H.-L. Le, S. Boyé-Péronne, S. Hartweg, M. Roy-Chowdhury, G. A. Garcia, J.-C. Loison, and B. Gans, Refining Thermochemical Properties of CF, SiF, and Their Cations by Combining Photoelectron Spectroscopy, Quantum Chemical Calculations, and the Active Thermochemical Tables Approach Phys. Chem. Chem. Phys. 25, 30838-30847 (2023) [DOI: 10.1039/D3CP04244H]
6		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]
7		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 [6] and Ruscic and Bross[7]).
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.