Selected ATcT [1, 2] enthalpy of formation based on version 1.172 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.156 to include species relevant to a study of photodissociation of formamide[4].

iso-Pentane

Formula: CH3CH2CH(CH3)2 (g)

CAS RN: 78-78-4

ATcT ID: 78-78-4*0

SMILES: CCC(C)C

InChI: InChI=1S/C5H12/c1-4-5(2)3/h5H,4H2,1-3H3

InChIKey: QWTDNUCVQCZILF-UHFFFAOYSA-N

Hills Formula: C5H12

2D Image:

Aliases: CH3CH2CH(CH3)2; iso-Pentane; Isopentane; i-Pentane; 2-Methylbutane; Methylbutane; 1,1,2-Trimethylethane; 1,1-Dimethylpropane; Exxsol Isopentane S; Borger Isopentane; NSC 119476; R 601A; CH3CH2CH(CH3)CH3; (CH3)2CHCH2CH3; CH3CH(CH3)CH2CH3

Relative Molecular Mass: 72.1488 ± 0.0041

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
-118.93	-152.98	± 0.39	kJ/mol

3D Image of CH3CH2CH(CH3)2 (g)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of CH3CH2CH(CH3)2 (g)

The 20 contributors listed below account only for 73.7% of the provenance of Δ_fH° of CH3CH2CH(CH3)2 (g).
A total of 66 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
15.5	3933.1	CH3CH2CH(CH3)2 (l) + 8 O2 (g) → 5 CO2 (g) + 6 H2O (cr,l)	Δ_rH°(298.15 K) = -837.56 ± 0.20 kcal/mol	Good 1970
12.9	3932.1	CH3CH2CH(CH3)2 (g) + 8 O2 (g) → 5 CO2 (g) + 6 H2O (cr,l)	Δ_rH°(298.15 K) = -843.30 ± 0.22 kcal/mol	Pilcher 1967
6.6	3943.1	C(CH3)4 (l) → CH3CH2CH(CH3)2 (l)	Δ_rH°(298.15 K) = 2.86 ± 0.24 kcal/mol	Good 1970
6.5	3934.1	CH3CH2CH(CH3)2 (l) → CH3CH2CH2CH2CH3 (cr,l)	Δ_rH°(298.15 K) = 1.12 ± 0.26 kcal/mol	Good 1970
5.1	3931.1	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
4.3	3930.1	CH3CH2CH(CH3)2 (g) → CH3CH2CH2CH2CH3 (g)	Δ_rH°(298.15 K) = 1.68 ± 0.32 kcal/mol	Pilcher 1967
3.7	3939.1	C(CH3)4 (g) → CH3CH2CH(CH3)2 (g)	Δ_rH°(298.15 K) = 3.43 ± 0.32 kcal/mol	Pilcher 1967
3.3	4015.1	CH3CH2CH2CH(CH3)2 (cr,l) → CH3CH2CH2CH2CH2CH3 (cr,l)	Δ_rH°(298.15 K) = 1.30 ± 0.21 kcal/mol	Prosen 1941
2.7	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
1.5	4012.5	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.46 ± 0.85 kcal/mol	Karton 2009b, Ruscic W1RO
1.4	2375.1	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	3941.1	C(CH3)4 (l) + 8 O2 (g) → 5 CO2 (g) + 6 H2O (cr,l)	Δ_rH°(298.15 K) = -834.70 ± 0.14 kcal/mol	Good 1970
1.3	4012.2	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.50 ± 0.90 kcal/mol	Ruscic G4
1.3	4012.4	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.59 ± 0.90 kcal/mol	Ruscic CBS-n
1.3	4012.1	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.51 ± 0.90 kcal/mol	Ruscic G3X
1.0	4012.3	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.50 ± 1.00 kcal/mol	Ruscic CBS-n
0.8	2373.7	CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -890.578 ± 0.078 kJ/mol	Schley 2010
0.8	2228.7	C (graphite) + O2 (g) → CO2 (g)	Δ_rH°(298.15 K) = -393.464 ± 0.024 kJ/mol	Hawtin 1966, note CO2e
0.6	3931.5	CH3CH2CH(CH3)2 (g) + CH3CH2CH3 (g) → CH(CH3)3 (g) + CH3CH2CH2CH3 (g)	Δ_rH°(0 K) = -0.61 ± 0.85 kcal/mol	Karton 2009b, Ruscic W1RO
0.6	3930.6	CH3CH2CH(CH3)2 (g) → CH3CH2CH2CH2CH3 (g)	Δ_rH°(0 K) = 1.22 ± 0.85 kcal/mol	Karton 2009b, Ruscic W1RO

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH3CH2CH(CH3)2 (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
99.5	iso-Pentane	CH3CH2CH(CH3)2 (l)		-178.20	± 0.39	kJ/mol	72.1488 ± 0.0041	78-78-4*500
35.6	2-Methylpentane	CH3CH2CH2CH(CH3)2 (g)	-134.48	-173.73	± 0.73	kJ/mol	86.1754 ± 0.0049	107-83-5*0
35.4	2-Methylpentane	CH3CH2CH2CH(CH3)2 (cr,l)	-180.18	-203.83	± 0.73	kJ/mol	86.1754 ± 0.0049	107-83-5*500
35.1	n-Pentane	CH3CH2CH2CH2CH3 (g)	-114.19	-146.06	± 0.29	kJ/mol	72.1488 ± 0.0041	109-66-0*0
35.1	n-Pentane	CH3CH2CH2CH2CH3 (cr,l)	-155.83	-172.80	± 0.29	kJ/mol	72.1488 ± 0.0041	109-66-0*500
32.7	Carbonic acid	C(O)(OH)2 (aq, undissoc)		-698.673	± 0.028	kJ/mol	62.0248 ± 0.0012	463-79-6*1000
32.6	neo-Pentane	C(CH3)4 (l)		-189.54	± 0.38	kJ/mol	72.1488 ± 0.0041	463-82-1*500
32.6	neo-Pentane	C(CH3)4 (g)	-134.27	-167.15	± 0.38	kJ/mol	72.1488 ± 0.0041	463-82-1*0
30.7	n-Hexane	CH3CH2CH2CH2CH2CH3 (cr,l)	-179.85	-198.51	± 0.32	kJ/mol	86.1754 ± 0.0049	110-54-3*500
30.7	Water	H2O (cr,l)	-286.276	-285.804	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*500

Most Influential reactions involving CH3CH2CH(CH3)2 (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
0.627	3935.2	CH3CH2CH(CH3)2 (l) → CH3CH2CH(CH3)2 (g)	Δ_rH°(298.15 K) = 6.029 ± 0.011 kcal/mol	Good 1970, Scott 1951
0.369	3935.1	CH3CH2CH(CH3)2 (l) → CH3CH2CH(CH3)2 (g)	Δ_rH°(298.15 K) = 25.22 ± 0.06 kJ/mol	Majer 1985
0.150	3932.1	CH3CH2CH(CH3)2 (g) + 8 O2 (g) → 5 CO2 (g) + 6 H2O (cr,l)	Δ_rH°(298.15 K) = -843.30 ± 0.22 kcal/mol	Pilcher 1967
0.107	3939.1	C(CH3)4 (g) → CH3CH2CH(CH3)2 (g)	Δ_rH°(298.15 K) = 3.43 ± 0.32 kcal/mol	Pilcher 1967
0.105	3931.1	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
0.084	3930.1	CH3CH2CH(CH3)2 (g) → CH3CH2CH2CH2CH3 (g)	Δ_rH°(298.15 K) = 1.68 ± 0.32 kcal/mol	Pilcher 1967
0.056	4023.5	CH3CH(CH3)CH(CH3)CH3 (g) + CH3CH2CH3 (g) → CH3CH2CH(CH3)2 (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.42 ± 0.85 kcal/mol	Karton 2009b, Ruscic W1RO
0.056	4012.5	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.46 ± 0.85 kcal/mol	Karton 2009b, Ruscic W1RO
0.052	4029.5	CH3CH2C(CH3)3 (g) + CH(CH3)3 (g) → C(CH3)4 (g) + CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = -0.29 ± 0.85 kcal/mol	Karton 2009b, Ruscic W1RO
0.050	4023.1	CH3CH(CH3)CH(CH3)CH3 (g) + CH3CH2CH3 (g) → CH3CH2CH(CH3)2 (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.28 ± 0.90 kcal/mol	Ruscic G3X
0.050	4023.4	CH3CH(CH3)CH(CH3)CH3 (g) + CH3CH2CH3 (g) → CH3CH2CH(CH3)2 (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.33 ± 0.90 kcal/mol	Ruscic CBS-n
0.050	4023.2	CH3CH(CH3)CH(CH3)CH3 (g) + CH3CH2CH3 (g) → CH3CH2CH(CH3)2 (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.17 ± 0.90 kcal/mol	Ruscic G4
0.050	4012.2	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.50 ± 0.90 kcal/mol	Ruscic G4
0.050	4012.1	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.51 ± 0.90 kcal/mol	Ruscic G3X
0.050	4012.4	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.59 ± 0.90 kcal/mol	Ruscic CBS-n
0.047	4029.2	CH3CH2C(CH3)3 (g) + CH(CH3)3 (g) → C(CH3)4 (g) + CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = -0.14 ± 0.90 kcal/mol	Ruscic G4
0.047	4029.1	CH3CH2C(CH3)3 (g) + CH(CH3)3 (g) → C(CH3)4 (g) + CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = -0.17 ± 0.90 kcal/mol	Ruscic G3X
0.047	4029.4	CH3CH2C(CH3)3 (g) + CH(CH3)3 (g) → C(CH3)4 (g) + CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = -0.64 ± 0.90 kcal/mol	Ruscic CBS-n
0.040	4023.3	CH3CH(CH3)CH(CH3)CH3 (g) + CH3CH2CH3 (g) → CH3CH2CH(CH3)2 (g) + CH(CH3)3 (g)	Δ_rH°(0 K) = -1.17 ± 1.00 kcal/mol	Ruscic CBS-n
0.040	4012.3	CH3CH2CH2CH(CH3)2 (g) + CH(CH3)3 (g) → 2 CH3CH2CH(CH3)2 (g)	Δ_rH°(0 K) = 0.50 ± 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. 1.172 of the Thermochemical Network (2024); available at ATcT.anl.gov
4		K. L. Caster, N. A. Seifert, B. Ruscic, A. W. Jasper, and K. Prozument, Dynamics of HCN, NHC, and HNCO Formation in the 193 nm Photodissociation of Formamide J. Phys. Chem. A (in press) (2024) [DOI: 10.1021/acs.jpca.4c02232]
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.