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].

Methylidyne

Formula: CH (g, quartet)

CAS RN: 3315-37-5

ATcT ID: 3315-37-5*2

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
664.70	668.03	± 0.52	kJ/mol

3D Image of CH (g, quartet)

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

The 20 contributors listed below account only for 81.2% of the provenance of Δ_fH° of CH (g, quartet).
A total of 43 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
42.3	2449.1	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 0.742 ± 0.008 eV	Kasdan 1975
18.0	5686.3	NCN (g) + H (g) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = -2.20 ± 1.0 kJ/mol	Harding 2018
3.0	2449.3	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 0.760 ± 0.030 eV	Kalemos 1999, est unc
3.0	2449.2	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 0.74 ± 0.03 eV	Goebbert 2012
2.2	5978.1	CH (g, quartet) + N2 (g) → HCN (g) + N (g, quartet)	Δ_rH°(0 K) = -15.28 ± 0.8 kcal/mol	Harding 2008a, est unc
1.4	2449.5	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 5897 ± 350 cm-1	Hettema 1994, est unc
1.1	2450.1	[CH]- (g) → CH (g, quartet)	Δ_rH°(0 K) = 1.94 ± 0.05 eV	Feldmann 1970
1.0	2441.9	CH (g, quartet) → C (g) + H (g)	Δ_rH°(0 K) = 2.671 ± 0.045 (×1.164) eV	Kalemos 1999, est unc
0.9	2448.8	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 6029 ± 420 cm-1	Ruscic W1RO
0.8	2448.4	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 6152 ± 450 cm-1	Ruscic G4
0.8	2448.7	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 6159 ± 455 cm-1	Ruscic CBS-n
0.8	5716.1	HNCN (g, doublet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 81.01 ± 1.2 kcal/mol	Harding 2008a, est unc
0.7	2448.3	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 5843 ± 490 cm-1	Ruscic G3X
0.7	5748.1	HCNN (g, doublet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 45.79 ± 1.1 (×1.164) kcal/mol	Harding 2008a, est unc
0.7	5786.1	HNNC (g, doublet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 41.13 ± 1.2 kcal/mol	Harding 2008a, est unc
0.6	5674.10	NCN (g) → 2 N (g) + C (g)	Δ_rH°(0 K) = 1200.9 ± 1.0 kJ/mol	Harding 2018
0.6	5687.4	NCN (g) + H (g) → HCN (g) + N (g)	Δ_rH°(0 K) = -67.10 ± 1.0 kJ/mol	Harding 2018
0.6	2441.8	CH (g, quartet) → C (g) + H (g)	Δ_rH°(0 K) = 62.83 ± 1.50 kcal/mol	Ruscic W1RO
0.6	2449.9	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 17.45 ± 1.5 kcal/mol	Harding 2008a, est unc
0.6	2449.6	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 5671 ± 525 cm-1	Follmeg 1987, est unc

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH (g, quartet)

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
26.2	Ethylidyne	CH3C (g, quartet)	640.8	636.3	± 1.1	kJ/mol	27.0452 ± 0.0016	67624-57-1*2
21.6	Methanetetraylbisamidogen	NCN (g)	451.36	451.77	± 0.40	kJ/mol	40.02418 ± 0.00081	2669-76-3*0
15.3	Propylidyne	CH3CH2C (g, quartet)	624.8	613.3	± 1.3	kJ/mol	41.0718 ± 0.0024	85056-54-8*2
14.4	Cyanoamidogen anion	[NCN]- (g)	211.85	211.77	± 0.60	kJ/mol	40.02473 ± 0.00081	189879-95-6*0
11.7	Diazomethyl	HCNN (g, quartet)	652.7	649.8	± 1.3	kJ/mol	41.03212 ± 0.00082	20813-32-5*2
11.7	Diazomethyl	HCNN (g, c-quartet)	652.7	649.7	± 1.3	kJ/mol	41.03212 ± 0.00082	20813-32-5*22
11.6	Methylidyne	CH (g, doublet)	592.967	596.301	± 0.081	kJ/mol	13.01864 ± 0.00080	3315-37-5*1
11.6	Methylidyne	CH (g)	592.967	596.301	± 0.081	kJ/mol	13.01864 ± 0.00080	3315-37-5*0
11.6	Isocyanoamidogen	HNNC (g, c-quartet)	828.2	825.4	± 1.3	kJ/mol	41.03212 ± 0.00082	947408-73-3*22
11.6	Isocyanoamidogen	HNNC (g, quartet)	828.2	825.6	± 1.3	kJ/mol	41.03212 ± 0.00082	947408-73-3*2

Most Influential reactions involving CH (g, quartet)

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
0.433	2449.1	CH (g, doublet) → CH (g, quartet)	Δ_rH°(0 K) = 0.742 ± 0.008 eV	Kasdan 1975
0.333	5686.3	NCN (g) + H (g) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = -2.20 ± 1.0 kJ/mol	Harding 2018
0.074	2583.5	CH3C (g, quartet) + CH3 (g) → CH (g, quartet) + CH3CH2 (g)	Δ_rH°(0 K) = 1.21 ± 0.9 kcal/mol	Ruscic W1RO
0.073	2582.5	CH3C (g, quartet) + CH4 (g) → CH (g, quartet) + CH3CH3 (g)	Δ_rH°(0 K) = 5.01 ± 0.9 kcal/mol	Ruscic W1RO
0.060	2583.4	CH3C (g, quartet) + CH3 (g) → CH (g, quartet) + CH3CH2 (g)	Δ_rH°(0 K) = 1.56 ± 1.0 kcal/mol	Ruscic CBS-n
0.060	2583.2	CH3C (g, quartet) + CH3 (g) → CH (g, quartet) + CH3CH2 (g)	Δ_rH°(0 K) = 1.33 ± 1.0 kcal/mol	Ruscic G4
0.059	2582.2	CH3C (g, quartet) + CH4 (g) → CH (g, quartet) + CH3CH3 (g)	Δ_rH°(0 K) = 5.30 ± 1.0 kcal/mol	Ruscic G4
0.059	2582.4	CH3C (g, quartet) + CH4 (g) → CH (g, quartet) + CH3CH3 (g)	Δ_rH°(0 K) = 5.26 ± 1.0 kcal/mol	Ruscic CBS-n
0.057	5786.1	HNNC (g, doublet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 41.13 ± 1.2 kcal/mol	Harding 2008a, est unc
0.050	2583.1	CH3C (g, quartet) + CH3 (g) → CH (g, quartet) + CH3CH2 (g)	Δ_rH°(0 K) = 1.11 ± 1.1 kcal/mol	Ruscic G3X
0.049	2582.1	CH3C (g, quartet) + CH4 (g) → CH (g, quartet) + CH3CH3 (g)	Δ_rH°(0 K) = 4.62 ± 1.1 kcal/mol	Ruscic G3X
0.044	5749.5	HCNN (g, c-quartet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 3.08 ± 1.50 kcal/mol	Ruscic W1RO
0.040	5787.5	HNNC (g, c-quartet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = -39.59 ± 1.50 kcal/mol	Ruscic W1RO
0.039	5719.5	HNCN (g, t-quartet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 2.92 ± 1.50 kcal/mol	Ruscic W1RO
0.038	5749.4	HCNN (g, c-quartet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 4.41 ± 1.60 kcal/mol	Ruscic CBS-n
0.038	5749.2	HCNN (g, c-quartet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 1.84 ± 1.60 kcal/mol	Ruscic G4
0.035	2583.3	CH3C (g, quartet) + CH3 (g) → CH (g, quartet) + CH3CH2 (g)	Δ_rH°(0 K) = 1.58 ± 1.3 kcal/mol	Ruscic CBS-n
0.035	5787.2	HNNC (g, c-quartet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = -39.90 ± 1.60 kcal/mol	Ruscic G4
0.035	2582.3	CH3C (g, quartet) + CH4 (g) → CH (g, quartet) + CH3CH3 (g)	Δ_rH°(0 K) = 5.46 ± 1.3 kcal/mol	Ruscic CBS-n
0.034	5719.2	HNCN (g, t-quartet) → CH (g, quartet) + N2 (g)	Δ_rH°(0 K) = 2.16 ± 1.60 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.