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]

iso-Butane

Formula: CH(CH3)3 (g)

CAS RN: 75-28-5

ATcT ID: 75-28-5*0

SMILES: CC(C)C

InChI: InChI=1S/C4H10/c1-4(2)3/h4H,1-3H3

InChIKey: NNPPMTNAJDCUHE-UHFFFAOYSA-N

Hills Formula: C4H10

2D Image:

Aliases: CH(CH3)3; iso-Butane; Isobutane; i-Butane; 1,1-Dimethylethane; 2-Methylpropane; Trimethylmethane; i-C4H10; iso-C4H10; UN 1969; (CH3)3CH; HC(CH3)3; CH3CH(CH3)2; CH3CH(CH3)CH3

Relative Molecular Mass: 58.1222 ± 0.0033

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
-105.88	-134.48	± 0.28	kJ/mol

3D Image of CH(CH3)3 (g)

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Top contributors to the provenance of Δ_fH° of CH(CH3)3 (g)

The 20 contributors listed below account only for 60.1% of the provenance of Δ_fH° of CH(CH3)3 (g).
A total of 266 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
14.8	3482.1	CH(CH3)3 (g) + 13/2 O2 (g) → 4 CO2 (g) + 5 H2O (cr,l)	Δ_rH°(298.15 K) = -2868.98 ± 0.59 kJ/mol	Pittam 1972
6.9	3482.2	CH(CH3)3 (g) + 13/2 O2 (g) → 4 CO2 (g) + 5 H2O (cr,l)	Δ_rH°(298.15 K) = -685.36 ± 0.11 (×1.874) kcal/mol	Prosen 1951
4.6	3484.2	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(298.15 K) = 8.59 ± 0.79 kJ/mol	Prosen 1951
4.4	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
4.1	3484.5	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(380 K) = 2.32 ± 0.20 kcal/mol	Pines 1945, 2nd Law
3.9	3484.1	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(298.15 K) = 8.54 ± 0.86 kJ/mol	Pittam 1972
3.7	3543.1	CH2C(CH3)2 (g) + H2 (g) → CH(CH3)3 (g)	Δ_rH°(298.15 K) = -28.15 ± 0.10 kcal/mol	Kistiakowsky 1935a, as quoted by Cox 1970
2.8	3484.6	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rG°(380 K) = 0.70 ± 0.24 kcal/mol	Pines 1945, 3rd Law
2.8	3712.1	CH3CH2CH(CH3)2 (g) + CH3CH2CH3 (g) → CH(CH3)3 (g) + CH3CH2CH2CH3 (g)	Δ_rH°(298.15 K) = -0.48 ± 0.31 kcal/mol	Prosen 1945
2.2	3542.1	CH2C(CH3)2 (g) + 6 O2 (g) → 4 CO2 (g) + 4 H2O (cr,l)	Δ_rH°(298.15 K) = -645.19 ± 0.25 kcal/mol	Prosen 1951, as quoted by Cox 1970
1.7	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
1.4	3481.1	4 CH4 (g) → CH(CH3)3 (g) + 3 H2 (g)	Δ_rH°(0 K) = 160.33 ± 2.00 kJ/mol	Klippenstein 2017
1.0	3483.8	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(0 K) = 1.68 ± 0.40 kcal/mol	Karton 2009b
1.0	2101.7	C (graphite) + O2 (g) → CO2 (g)	Δ_rH°(298.15 K) = -393.464 ± 0.024 kJ/mol	Hawtin 1966, note CO2e
0.8	3474.1	CH3CH2CH2CH3 (g) + 13/2 O2 (g) → 4 CO2 (g) + 5 H2O (cr,l)	Δ_rH°(298.15 K) = -2877.52 ± 0.63 kJ/mol	Pittam 1972
0.7	3483.9	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(0 K) = 7.43 ± 2.00 kJ/mol	Klippenstein 2017
0.7	3484.3	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(298.15 K) = 1.63 ± 0.15 (×3.221) kcal/mol	Rossini 1935
0.6	3541.1	4 CH4 (g) → CH2C(CH3)2 (g) + 4 H2 (g)	Δ_rH°(0 K) = 270.66 ± 2.00 kJ/mol	Klippenstein 2017
0.5	3480.8	CH(CH3)3 (g) → 4 C (g) + 10 H (g)	Δ_rH°(0 K) = 1222.51 ± 0.60 (×1.269) kcal/mol	Karton 2009b
0.5	3588.1	CH2CHCHCH2 (g) + 2 H2 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(355.15 K) = -57.079 ± 0.10 kcal/mol	Kistiakowsky 1936, Prosen 1945c

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH(CH3)3 (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
53.4	Isobutene	CH2C(CH3)2 (g)	4.18	-16.89	± 0.38	kJ/mol	56.1063 ± 0.0032	115-11-7*0
47.0	n-Butane	CH3CH2CH2CH3 (g)	-98.33	-125.64	± 0.24	kJ/mol	58.1222 ± 0.0033	106-97-8*0
36.8	Carbonic acid	C(O)(OH)2 (aq, undissoc)		-698.991	± 0.030	kJ/mol	62.0248 ± 0.0012	463-79-6*1000
35.6	Propane	CH3CH2CH3 (g)	-82.72	-105.00	± 0.16	kJ/mol	44.0956 ± 0.0025	74-98-6*0
34.9	Water	H2O (cr, l, eq.press.)	-286.269	-285.797	± 0.025	kJ/mol	18.01528 ± 0.00033	7732-18-5*499
34.9	Water	H2O (l, eq.press.)		-285.797	± 0.025	kJ/mol	18.01528 ± 0.00033	7732-18-5*589
34.9	Water	H2O (l)		-285.796	± 0.025	kJ/mol	18.01528 ± 0.00033	7732-18-5*590
34.9	Oxonium	[H3O]+ (aq)		-285.796	± 0.025	kJ/mol	19.02267 ± 0.00037	13968-08-6*800
34.9	Water	H2O (cr,l)	-286.268	-285.796	± 0.025	kJ/mol	18.01528 ± 0.00033	7732-18-5*500
34.9	Water	H2O (g)	-238.898	-241.801	± 0.025	kJ/mol	18.01528 ± 0.00033	7732-18-5*0

Most Influential reactions involving CH(CH3)3 (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
0.601	3543.1	CH2C(CH3)2 (g) + H2 (g) → CH(CH3)3 (g)	Δ_rH°(298.15 K) = -28.15 ± 0.10 kcal/mol	Kistiakowsky 1935a, as quoted by Cox 1970
0.192	3535.6	CH(CH3)3 (g) → (CH3)2CHCH2 (g) + H (g)	Δ_rH°(0 K) = 419.74 ± 2.00 kJ/mol	Klippenstein 2017
0.190	3482.1	CH(CH3)3 (g) + 13/2 O2 (g) → 4 CO2 (g) + 5 H2O (cr,l)	Δ_rH°(298.15 K) = -2868.98 ± 0.59 kJ/mol	Pittam 1972
0.179	7306.5	CH(CH(CHCH)) (g) + [(CH3)3C]- (g) → [C(CH(CHCH))]- (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -23.28 ± 0.8 kcal/mol	Ruscic W1RO
0.139	7361.5	CH3CH(CHCHCHCH) (g) + CH3CH2CH3 (g) → CH2(CHCHCHCH) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.30 ± 0.85 kcal/mol	Ruscic W1RO
0.134	3528.6	CH(CH3)3 (g) → (CH3)3C (g) + H (g)	Δ_rH°(0 K) = 397.50 ± 2.00 kJ/mol	Klippenstein 2017
0.128	3712.1	CH3CH2CH(CH3)2 (g) + CH3CH2CH3 (g) → CH(CH3)3 (g) + CH3CH2CH2CH3 (g)	Δ_rH°(298.15 K) = -0.48 ± 0.31 kcal/mol	Prosen 1945
0.124	7361.2	CH3CH(CHCHCHCH) (g) + CH3CH2CH3 (g) → CH2(CHCHCHCH) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.09 ± 0.90 kcal/mol	Ruscic G4
0.124	7361.1	CH3CH(CHCHCHCH) (g) + CH3CH2CH3 (g) → CH2(CHCHCHCH) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.09 ± 0.90 kcal/mol	Ruscic G3X
0.124	7361.4	CH3CH(CHCHCHCH) (g) + CH3CH2CH3 (g) → CH2(CHCHCHCH) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.08 ± 0.90 kcal/mol	Ruscic CBS-n
0.116	3582.5	CH3CH(CH2CH2) (g) + CH3CH2CH3 (g) → CH2(CH2CH2) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = 0.10 ± 0.85 kcal/mol	Ruscic W1RO
0.114	7306.2	CH(CH(CHCH)) (g) + [(CH3)3C]- (g) → [C(CH(CHCH))]- (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -23.46 ± 1.0 kcal/mol	Ruscic G4
0.113	3484.2	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(298.15 K) = 8.59 ± 0.79 kJ/mol	Prosen 1951
0.112	3525.1	(CH3)3C (g) + HBr (g) → CH(CH3)3 (g) + Br (g)	Δ_rG°(388 K) = -17.6 ± 2.2 kJ/mol	Russell 1988b, 3rd Law
0.103	3582.2	CH3CH(CH2CH2) (g) + CH3CH2CH3 (g) → CH2(CH2CH2) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -0.07 ± 0.90 kcal/mol	Ruscic G4
0.103	3582.4	CH3CH(CH2CH2) (g) + CH3CH2CH3 (g) → CH2(CH2CH2) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = 0.11 ± 0.90 kcal/mol	Ruscic CBS-n
0.103	3582.1	CH3CH(CH2CH2) (g) + CH3CH2CH3 (g) → CH2(CH2CH2) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = 0.06 ± 0.90 kcal/mol	Ruscic G3X
0.101	3484.5	CH(CH3)3 (g) → CH3CH2CH2CH3 (g)	Δ_rH°(380 K) = 2.32 ± 0.20 kcal/mol	Pines 1945, 2nd Law
0.100	7306.4	CH(CH(CHCH)) (g) + [(CH3)3C]- (g) → [C(CH(CHCH))]- (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -21.86 ± 1.0 (×1.067) kcal/mol	Ruscic CBS-n
0.100	7361.3	CH3CH(CHCHCHCH) (g) + CH3CH2CH3 (g) → CH2(CHCHCHCH) (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.09 ± 1.00 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. 1.124 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.