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].

Ethylidene

Formula: CH3CH (g, triplet)

CAS RN: 4218-50-2

ATcT ID: 4218-50-2*1

SMILES: [CH]C

InChI: InChI=1S/C2H4/c1-2/h1H,2H3

InChIKey: UUFQTNFCRMXOAE-UHFFFAOYSA-N

Hills Formula: C2H4

2D Image:

Aliases: CH3CH; Ethylidene; Methylcarbene; CHCH3; HCCH3

Relative Molecular Mass: 28.0532 ± 0.0016

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
361.29	354.28	± 0.48	kJ/mol

3D Image of CH3CH (g, triplet)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of CH3CH (g, triplet)

The 20 contributors listed below account only for 60.1% of the provenance of Δ_fH° of CH3CH (g, triplet).
A total of 131 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
9.4	2547.8	CH3CH (g, triplet) → CH2CH2 (g)	Δ_rH°(0 K) = -300.25 ± 1.5 kJ/mol	Klippenstein 2017
8.9	2549.9	CH3CH (g, triplet) + CH4 (g) → CH2 (g, triplet) + CH3CH3 (g)	Δ_rH°(0 K) = 27.86 ± 1.5 kJ/mol	Klippenstein 2017
8.5	2550.10	CH3CH (g, triplet) + CH3 (g) → CH2 (g, triplet) + CH3CH2 (g)	Δ_rH°(0 K) = 11.49 ± 1.5 kJ/mol	Klippenstein 2017
8.4	2546.1	CH3CH (g, triplet) → CH3CH (g, singlet)	Δ_rH°(0 K) = 12.5 ± 1. kJ/mol	Datta 2020, est unc
2.7	4243.6	CH3COH (g, syn singlet) + CH2 (g, triplet) → CH3CH (g, triplet) + HCOH (g, trans)	Δ_rH°(0 K) = 12.95 ± 2.0 kJ/mol	Klippenstein 2017
1.9	3323.5	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 0.81 ± 0.85 kcal/mol	Ruscic W1RO
1.8	2547.6	CH3CH (g, triplet) → CH2CH2 (g)	Δ_rH°(0 K) = -72.21 ± 0.8 kcal/mol	Nguyen 2008b
1.7	3363.1	3 CH4 (g) → CH3CH2CH (g, triplet gauche) + 3 H2 (g)	Δ_rH°(0 K) = 549.19 ± 2.0 kJ/mol	Klippenstein 2017
1.7	3323.4	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.16 ± 0.90 kcal/mol	Ruscic CBS-n
1.7	3323.1	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.23 ± 0.90 kcal/mol	Ruscic G3X
1.7	3323.2	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.20 ± 0.90 kcal/mol	Ruscic G4
1.5	2536.9	CH3CH (g, triplet) → 2 C (g) + 4 H (g)	Δ_rH°(0 K) = 459.69 ± 0.9 kcal/mol	Nguyen 2008b
1.4	2549.8	CH3CH (g, triplet) + CH4 (g) → CH2 (g, triplet) + CH3CH3 (g)	Δ_rH°(0 K) = 6.58 ± 0.9 kcal/mol	Ruscic W1RO
1.3	3323.3	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.22 ± 1.00 kcal/mol	Ruscic CBS-n
1.3	2550.9	CH3CH (g, triplet) + CH3 (g) → CH2 (g, triplet) + CH3CH2 (g)	Δ_rH°(0 K) = 2.78 ± 0.9 kcal/mol	Ruscic W1RO
1.1	2549.4	CH3CH (g, triplet) + CH4 (g) → CH2 (g, triplet) + CH3CH3 (g)	Δ_rH°(0 K) = 6.72 ± 1.0 kcal/mol	Ruscic G4
1.1	2549.7	CH3CH (g, triplet) + CH4 (g) → CH2 (g, triplet) + CH3CH3 (g)	Δ_rH°(0 K) = 6.66 ± 1.0 kcal/mol	Ruscic CBS-n
1.1	2550.8	CH3CH (g, triplet) + CH3 (g) → CH2 (g, triplet) + CH3CH2 (g)	Δ_rH°(0 K) = 2.97 ± 1.0 kcal/mol	Ruscic CBS-n
1.1	2550.5	CH3CH (g, triplet) + CH3 (g) → CH2 (g, triplet) + CH3CH2 (g)	Δ_rH°(0 K) = 2.75 ± 1.0 kcal/mol	Ruscic G4
1.0	3367.6	CH3CH2CH (g, triplet gauche) + CH3CH3 (g) → CH3CH (g, triplet) + CH3CH2CH3 (g)	Δ_rH°(0 K) = -2.89 ± 2.0 kJ/mol	Klippenstein 2017

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH3CH (g, triplet)

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	Ethylidene	CH3CH (g)	361.29	354.30	± 0.48	kJ/mol	28.0532 ± 0.0016	4218-50-2*0
38.2	1-Methylethylidene	CH3CCH3 (g, triplet)	326.9	313.7	± 1.2	kJ/mol	42.0797 ± 0.0024	40852-89-9*1
33.2	Ethylidene	CH3CH (g, singlet)	373.63	366.41	± 0.56	kJ/mol	28.0532 ± 0.0016	4218-50-2*2
30.0	Propylidene	CH3CH2CH (g)	349.49	335.80	± 0.92	kJ/mol	42.0797 ± 0.0024	6700-78-3*0
30.0	Propylidene	CH3CH2CH (g, triplet)	349.49	335.73	± 0.92	kJ/mol	42.0797 ± 0.0024	6700-78-3*1
30.0	Propylidene	CH3CH2CH (g, triplet gauche)	349.49	335.80	± 0.92	kJ/mol	42.0797 ± 0.0024	6700-78-3*11
18.2	Cyclopropylidene	C(CH2CH2) (g, triplet)	544.8	536.0	± 1.5	kJ/mol	40.0639 ± 0.0024	2143-70-6*2
17.6	1-Methylethylidene	CH3CCH3 (g, singlet)	316.06	302.15	± 0.97	kJ/mol	42.0797 ± 0.0024	40852-89-9*2
17.6	1-Methylethylidene	CH3CCH3 (g)	316.06	303.16	± 0.97	kJ/mol	42.0797 ± 0.0024	40852-89-9*0
15.7	1-Hydroxyethylidene	CH3COH (g, anti singlet)	57.44	47.06	± 0.77	kJ/mol	44.0526 ± 0.0017	30967-49-8*21

Most Influential reactions involving CH3CH (g, triplet)

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	2545.1	CH3CH (g) → CH3CH (g, triplet)	Δ_rH°(0 K) = 0 ± 0 cm-1	triv, Ruscic G3B3
0.356	2546.1	CH3CH (g, triplet) → CH3CH (g, singlet)	Δ_rH°(0 K) = 12.5 ± 1. kJ/mol	Datta 2020, est unc
0.215	4243.6	CH3COH (g, syn singlet) + CH2 (g, triplet) → CH3CH (g, triplet) + HCOH (g, trans)	Δ_rH°(0 K) = 12.95 ± 2.0 kJ/mol	Klippenstein 2017
0.198	3367.6	CH3CH2CH (g, triplet gauche) + CH3CH3 (g) → CH3CH (g, triplet) + CH3CH2CH3 (g)	Δ_rH°(0 K) = -2.89 ± 2.0 kJ/mol	Klippenstein 2017
0.194	2538.4	CH3CH (g, triplet) → [CH3CH]+ (g)	Δ_rH°(0 K) = 8.500 ± 0.075 eV	Ruscic CBS-n
0.135	2540.8	[CH3CH]- (g) → CH3CH (g, triplet)	Δ_rH°(0 K) = 0.368 ± 0.050 eV	Ruscic W1RO
0.111	2538.2	CH3CH (g, triplet) → [CH3CH]+ (g)	Δ_rH°(0 K) = 8.538 ± 0.099 eV	Ruscic G3
0.110	3323.5	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 0.81 ± 0.85 kcal/mol	Ruscic W1RO
0.105	2550.10	CH3CH (g, triplet) + CH3 (g) → CH2 (g, triplet) + CH3CH2 (g)	Δ_rH°(0 K) = 11.49 ± 1.5 kJ/mol	Klippenstein 2017
0.098	2547.8	CH3CH (g, triplet) → CH2CH2 (g)	Δ_rH°(0 K) = -300.25 ± 1.5 kJ/mol	Klippenstein 2017
0.098	2549.9	CH3CH (g, triplet) + CH4 (g) → CH2 (g, triplet) + CH3CH3 (g)	Δ_rH°(0 K) = 27.86 ± 1.5 kJ/mol	Klippenstein 2017
0.098	3323.2	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.20 ± 0.90 kcal/mol	Ruscic G4
0.098	3323.1	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.23 ± 0.90 kcal/mol	Ruscic G3X
0.098	3323.4	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.16 ± 0.90 kcal/mol	Ruscic CBS-n
0.091	2540.4	[CH3CH]- (g) → CH3CH (g, triplet)	Δ_rH°(0 K) = 0.389 ± 0.061 eV	Ruscic G4
0.079	3323.3	CH3CCH3 (g, triplet) + CH2 (g, triplet) → 2 CH3CH (g, triplet)	Δ_rH°(0 K) = 1.22 ± 1.00 kcal/mol	Ruscic CBS-n
0.062	3367.5	CH3CH2CH (g, triplet gauche) + CH3CH3 (g) → CH3CH (g, triplet) + CH3CH2CH3 (g)	Δ_rH°(0 K) = -0.71 ± 0.85 kcal/mol	Ruscic W1RO
0.057	4242.5	CH3COH (g, anti singlet) + CH2 (g, triplet) → CH3CH (g, triplet) + HCOH (g, trans)	Δ_rH°(0 K) = 6.15 ± 0.85 kcal/mol	Ruscic W1RO
0.056	3367.1	CH3CH2CH (g, triplet gauche) + CH3CH3 (g) → CH3CH (g, triplet) + CH3CH2CH3 (g)	Δ_rH°(0 K) = -0.71 ± 0.90 kcal/mol	Ruscic G3X
0.056	3367.4	CH3CH2CH (g, triplet gauche) + CH3CH3 (g) → CH3CH (g, triplet) + CH3CH2CH3 (g)	Δ_rH°(0 K) = -0.61 ± 0.90 kcal/mol	Ruscic CBS-n

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.