Selected ATcT [1, 2] enthalpy of formation based on version 1.124 of the Thermochemical Network [3]

This version of ATcT results was generated by additional expansion of version 1.122x [4] to include additional information relevant to the study of thermophysical and thermochemical properties of CH2 and CH3 using nonrigid rotor anharmonic oscillator (NRRAO) partition functions [5], the development and benchmarking of a state-of-the-art computational approach that aims to reproduce total atomization energies of small molecules within 10–15 cm^-1 [6], as well as the study of the reversible reaction C₂H₃ + H₂ ⇌ C₂H₄ + H ⇌ C₂H₅ [7]

Ethyl

Formula: CH3CH2 (g)

CAS RN: 2025-56-1

ATcT ID: 2025-56-1*0

SMILES: C[CH2]

InChI: InChI=1S/C2H5/c1-2/h1H2,2H3

InChIKey: QUPDWYMUPZLYJZ-UHFFFAOYSA-N

Hills Formula: C2H5

2D Image:

Aliases: CH3CH2; Ethyl; Ethyl radical

Relative Molecular Mass: 29.0611 ± 0.0016

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
131.38	120.63	± 0.22	kJ/mol

3D Image of CH3CH2 (g)

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Top contributors to the provenance of Δ_fH° of CH3CH2 (g)

The 20 contributors listed below account only for 44.5% of the provenance of Δ_fH° of CH3CH2 (g).
A total of 502 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
15.8	2366.1	CH3CH2 (g) → H (g) + CH2CH2 (g)	Δ_rG°(775 K) = 19.71 ± 0.10 kcal/mol	Brouard 1986, 3rd Law
4.3	2366.2	CH3CH2 (g) → H (g) + CH2CH2 (g)	Δ_rG°(800 K) = 19.17 ± 0.19 kcal/mol	Brouard 1986, 3rd Law
2.6	2370.3	CH3CH2 (g) + HBr (g) → CH3CH3 (g) + Br (g)	Δ_rG°(298.15 K) = -10.20 ± 0.15 (×1.477) kcal/mol	Dobis 1997, Fettis 1960, 3rd Law
2.5	2356.1	CH3CH2 (g) → [CH3CH2]+ (g)	Δ_rH°(0 K) = 8.117 ± 0.008 eV	Ruscic 1989b
2.3	2366.3	CH3CH2 (g) → H (g) + CH2CH2 (g)	Δ_rG°(825 K) = 18.26 ± 0.11 (×2.378) kcal/mol	Brouard 1986, 3rd Law
1.8	2245.1	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	2360.1	2 CH4 (g) → CH3CH2 (g) + 3/2 H2 (g)	Δ_rH°(0 K) = 264.07 ± 1.5 kJ/mol	Klippenstein 2017
1.6	2356.15	CH3CH2 (g) → [CH3CH2]+ (g)	Δ_rH°(0 K) = 8.124 ± 0.010 eV	Lau 2005
1.4	2370.5	CH3CH2 (g) + HBr (g) → CH3CH3 (g) + Br (g)	Δ_rG°(298.15 K) = -10.12 ± 0.13 (×2.327) kcal/mol	Dobis 1997, Amphlett 1968, 3rd Law
1.2	2397.1	CH2CH2 (g) + 3 O2 (g) → 2 CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -1411.18 ± 0.30 kJ/mol	Rossini 1937
1.2	2550.6	CH2NH2 (g) + CH4 (g) → CH3CH2 (g) + NH3 (g)	Δ_rH°(0 K) = -0.52 ± 1.5 kJ/mol	Klippenstein 2017
1.1	120.2	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
1.0	2368.2	CH3CH2 (g) + HBr (g) → CH3CH3 (g) + Br (g)	Δ_rH°(450 K) = -57.5 ± 1.5 kJ/mol	Ferrell 1998, 2nd Law, est unc
0.9	2418.10	CH3CH (g, triplet) + CH3 (g) → CH2 (g, triplet) + CH3CH2 (g)	Δ_rH°(0 K) = 11.49 ± 1.5 kJ/mol	Klippenstein 2017
0.8	2337.1	CH3CH3 (g) + 7/2 O2 (g) → 2 CO2 (g) + 3 H2O (cr,l)	Δ_rH°(298.15 K) = -1560.68 ± 0.25 (×1.445) kJ/mol	Pittam 1972
0.7	2368.4	CH3CH2 (g) + HBr (g) → CH3CH3 (g) + Br (g)	Δ_rH°(367 K) = -57.5 ± 1.7 kJ/mol	Seakins 1992, 2nd Law
0.7	5850.1	CH3CH2Br (g) → [CH3CH2]+ (g) + Br (g)	Δ_rH°(0 K) = 11.130 ± 0.005 eV	Baer 2000
0.6	2368.1	CH3CH2 (g) + HBr (g) → CH3CH3 (g) + Br (g)	Δ_rG°(450 K) = -38.3 ± 1.5 (×1.215) kJ/mol	Ferrell 1998, 3rd Law, est unc
0.6	2369.6	CH3CH2 (g) + HBr (g) → CH3CH3 (g) + Br (g)	Δ_rH°(298.15 K) = -14.08 ± 0.28 (×1.576) kcal/mol	Dobis 1997, Seakins 1992, Nicovich 1991, Fettis 1960, 2nd Law
0.6	2361.9	CH3CH3 (g) → CH3CH2 (g) + H (g)	Δ_rH°(0 K) = 416.0 ± 2.1 kJ/mol	Marshall 1999

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH3CH2 (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
40.4	Ethylene	CH2CH2 (g)	60.89	52.38	± 0.12	kJ/mol	28.0532 ± 0.0016	74-85-1*0
40.4	Ethane	CH3CH3 (g)	-68.39	-84.02	± 0.12	kJ/mol	30.0690 ± 0.0017	74-84-0*0
40.4	Ethylene cation	[CH2CH2]+ (g)	1075.21	1067.99	± 0.12	kJ/mol	28.0526 ± 0.0016	34470-02-5*0
31.0	Propane	CH3CH2CH3 (g)	-82.72	-105.00	± 0.16	kJ/mol	44.0956 ± 0.0025	74-98-6*0
29.6	Ethylium	[CH3CH2]+ (g)	914.95	902.88	± 0.30	kJ/mol	29.0606 ± 0.0016	14936-94-8*0
24.1	Propene	CH3CHCH2 (g)	34.85	20.02	± 0.19	kJ/mol	42.0797 ± 0.0024	115-07-1*0
24.0	Propylene cation	[CH3CHCH2]+ (g)	975.14	961.61	± 0.19	kJ/mol	42.0792 ± 0.0024	34504-10-4*0
22.9	Carbon	C (g)	711.404	716.889	± 0.044	kJ/mol	12.01070 ± 0.00080	7440-44-0*0
22.9	Carbon	C (g, triplet)	711.404	716.889	± 0.044	kJ/mol	12.01070 ± 0.00080	7440-44-0*1
22.9	Carbon	C (g, quintuplet)	1114.967	1120.114	± 0.044	kJ/mol	12.01070 ± 0.00080	7440-44-0*3

Most Influential reactions involving CH3CH2 (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
0.242	3497.5	CH3CH2CH2CH2 (g) + [CH3CH2]+ (g) → [CH3CH2CH2CH2]+ (g) + CH3CH2 (g)	Δ_rH°(0 K) = -0.614 ± 0.020 eV	Ruscic W1RO
0.237	4826.6	CH2C(O)OH (g, syn) + CH3CH3 (g) → CH3C(O)OH (g, syn) + CH3CH2 (g)	Δ_rH°(0 K) = 7.41 ± 2.00 kJ/mol	Klippenstein 2017
0.218	2366.1	CH3CH2 (g) → H (g) + CH2CH2 (g)	Δ_rG°(775 K) = 19.71 ± 0.10 kcal/mol	Brouard 1986, 3rd Law
0.217	4811.9	HC(O)OCH2 (g, syn) + CH3CH3 (g) → HC(O)OCH3 (g, syn) + CH3CH2 (g)	Δ_rH°(0 K) = 4.04 ± 2.00 kJ/mol	Klippenstein 2017
0.159	2356.1	CH3CH2 (g) → [CH3CH2]+ (g)	Δ_rH°(0 K) = 8.117 ± 0.008 eV	Ruscic 1989b
0.102	2356.15	CH3CH2 (g) → [CH3CH2]+ (g)	Δ_rH°(0 K) = 8.124 ± 0.010 eV	Lau 2005
0.099	2418.10	CH3CH (g, triplet) + CH3 (g) → CH2 (g, triplet) + CH3CH2 (g)	Δ_rH°(0 K) = 11.49 ± 1.5 kJ/mol	Klippenstein 2017
0.098	6600.5	CH2N(O)O (g) + CH3CH3 (g) → CH3N(O)O (g) + CH3CH2 (g)	Δ_rH°(0 K) = 0.59 ± 0.85 kcal/mol	Ruscic W1RO
0.097	2460.5	[CH3C]+ (g) + CH3 (g) → [CH]+ (g) + CH3CH2 (g)	Δ_rH°(0 K) = 65.21 ± 0.9 kcal/mol	Ruscic W1RO
0.096	2458.5	[CH3C]- (g) + CH3 (g) → [CH]- (g) + CH3CH2 (g)	Δ_rH°(0 K) = 0.13 ± 0.9 kcal/mol	Ruscic W1RO
0.088	4812.8	HC(O)OCH2 (g, anti) + CH3CH3 (g) → HC(O)OCH3 (g, anti) + CH3CH2 (g)	Δ_rH°(0 K) = 2.11 ± 0.85 kcal/mol	Ruscic W1RO
0.087	6600.2	CH2N(O)O (g) + CH3CH3 (g) → CH3N(O)O (g) + CH3CH2 (g)	Δ_rH°(0 K) = 0.28 ± 0.90 kcal/mol	Ruscic G4
0.087	6600.1	CH2N(O)O (g) + CH3CH3 (g) → CH3N(O)O (g) + CH3CH2 (g)	Δ_rH°(0 K) = 0.65 ± 0.90 kcal/mol	Ruscic G3X
0.087	6600.4	CH2N(O)O (g) + CH3CH3 (g) → CH3N(O)O (g) + CH3CH2 (g)	Δ_rH°(0 K) = 0.41 ± 0.90 kcal/mol	Ruscic CBS-n
0.086	3235.5	CH3CH2C (g, quartet) + CH3 (g) → CH3C (g, quartet) + CH3CH2 (g)	Δ_rH°(0 K) = -0.80 ± 0.85 kcal/mol	Ruscic W1RO
0.082	4827.5	CH2C(O)OH (g, anti) + CH3CH3 (g) → CH3C(O)OH (g, anti) + CH3CH2 (g)	Δ_rH°(0 K) = 1.62 ± 0.9 kcal/mol	Ruscic W1RO
0.080	3233.5	CH3CH2C (g, doublet) + CH3 (g) → CH3C (g, doublet) + CH3CH2 (g)	Δ_rH°(0 K) = -0.80 ± 0.85 kcal/mol	Ruscic W1RO
0.079	4812.4	HC(O)OCH2 (g, anti) + CH3CH3 (g) → HC(O)OCH3 (g, anti) + CH3CH2 (g)	Δ_rH°(0 K) = 2.44 ± 0.90 kcal/mol	Ruscic G4
0.079	4812.7	HC(O)OCH2 (g, anti) + CH3CH3 (g) → HC(O)OCH3 (g, anti) + CH3CH2 (g)	Δ_rH°(0 K) = 2.08 ± 0.90 kcal/mol	Ruscic CBS-n
0.079	4812.3	HC(O)OCH2 (g, anti) + CH3CH3 (g) → HC(O)OCH3 (g, anti) + CH3CH2 (g)	Δ_rH°(0 K) = 1.93 ± 0.90 kcal/mol	Ruscic G3X

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. 1.124 of the Thermochemical Network, Argonne National Laboratory, Lemont, Illinois 2022; available at ATcT.anl.gov [DOI: 10.17038/CSE/1885923]
4		Y. Ren, L. Zhou, A. Mellouki, V. Daële, M. Idir, S. S. Brown, B. Ruscic, Robert S. Paton, M. R. McGillen, and A. R. Ravishankara, Reactions of NO3 with Aromatic Aldehydes: Gas-Phase Kinetics and Insights into the Mechanism of the Reaction. Atmos. Chem. Phys. 21, 13537-13551 (2021) [DOI: 10.5194/acp2021-228]
5		B. Ruscic and D. H. Bross, Active Thermochemical Tables: The Thermophysical and Thermochemical Properties of Methyl, CH3, and Methylene, CH2, Corrected for Nonrigid Rotor and Anharmonic Oscillator Effects. Mol. Phys. e1969046 (2021) [DOI: 10.1080/00268976.2021.1969046]
6		J. H. Thorpe, J. L. Kilburn, D. Feller, P. B. Changala, D. H. Bross, B. Ruscic, and J. F. Stanton, Elaborated Thermochemical Treatment of HF, CO, N2, and H2O: Insight into HEAT and Its Extensions J. Chem. Phys. 155, 184109 (2021) [DOI: 10.1063/5.0069322]
7		T. L. Nguyen, D. H. Bross, B. Ruscic, G. B. Ellison, and J. F. Stanton, Mechanism, Thermochemistry, and Kinetics of the Reversible Reactions: C2H3 + H2 ⇌ C2H4 + H ⇌ C2H5. Faraday Discuss. , (Advance Article) (2022) [DOI: 10.1039/D1FD00124H]
8		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]
9		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 [8,9]).
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.