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].

Isoprene

Formula: CH2C(CH3)CHCH2 (cr,l)

CAS RN: 78-79-5

ATcT ID: 78-79-5*500

SMILES: CC(=C)C=C

InChI: InChI=1S/C5H8/c1-4-5(2)3/h4H,1-2H2,3H3

InChIKey: RRHGJUQNOFWUDK-UHFFFAOYSA-N

Hills Formula: C5H8

2D Image:

Aliases: CH2C(CH3)CHCH2; Isoprene; 2-Methyl-1,3-butadiene; 2-Methylbutadiene; Isopentadiene; beta-Methylbivinyl; UN 1218; NSC 9237

Relative Molecular Mass: 68.1170 ± 0.0040

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
	48.97	± 0.69	kJ/mol

Top contributors to the provenance of Δ_fH° of CH2C(CH3)CHCH2 (cr,l)

The 20 contributors listed below account for 90.7% of the provenance of Δ_fH° of CH2C(CH3)CHCH2 (cr,l).

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
38.9	4000.1	CH2C(CH3)CHCH2 (g) + 7 O2 (g) → 5 CO2 (g) + 4 H2O (cr,l)	Δ_rH°(298.15 K) = -3186.53 ± 0.96 kJ/mol	Fraser 1955
17.3	4001.1	CH2C(CH3)CHCH2 (cr,l) + 7 O2 (g) → 5 CO2 (g) + 4 H2O (cr,l)	Δ_rH°(298.15 K) = -3158.5 ± 1.6 kJ/mol	Jessup 1938a, Fraser 1955
7.1	4002.3	CH2C(CH3)CHCH2 (cr,l) → CH2C(CH3)CHCH2 (g)	Δ_rH°(298.15 K) = 6.40 ± 0.06 kcal/mol	Bekkedahl 1936, as quoted by Cox 1970
2.4	3997.5	CH2C(CH3)CHCH2 (g) + CH2CH2 (g) → CH2CHCHCH2 (g) + CH3CHCH2 (g)	Δ_rH°(0 K) = 0.64 ± 0.85 kcal/mol	Ruscic W1RO
2.2	3998.5	CH2C(CH3)CHCH2 (g) + CH3CH3 (g) → CH2CHCHCH2 (g) + CH3CH2CH3 (g)	Δ_rH°(0 K) = 3.40 ± 0.9 kcal/mol	Ruscic W1RO
2.1	3997.2	CH2C(CH3)CHCH2 (g) + CH2CH2 (g) → CH2CHCHCH2 (g) + CH3CHCH2 (g)	Δ_rH°(0 K) = 0.84 ± 0.90 kcal/mol	Ruscic G4
2.1	3997.4	CH2C(CH3)CHCH2 (g) + CH2CH2 (g) → CH2CHCHCH2 (g) + CH3CHCH2 (g)	Δ_rH°(0 K) = 0.81 ± 0.90 kcal/mol	Ruscic CBS-n
2.1	3997.1	CH2C(CH3)CHCH2 (g) + CH2CH2 (g) → CH2CHCHCH2 (g) + CH3CHCH2 (g)	Δ_rH°(0 K) = 0.90 ± 0.90 kcal/mol	Ruscic G3X
1.7	3998.4	CH2C(CH3)CHCH2 (g) + CH3CH3 (g) → CH2CHCHCH2 (g) + CH3CH2CH3 (g)	Δ_rH°(0 K) = 3.65 ± 1.0 kcal/mol	Ruscic CBS-n
1.7	3998.2	CH2C(CH3)CHCH2 (g) + CH3CH3 (g) → CH2CHCHCH2 (g) + CH3CH2CH3 (g)	Δ_rH°(0 K) = 3.56 ± 1.0 kcal/mol	Ruscic G4
1.7	3997.3	CH2C(CH3)CHCH2 (g) + CH2CH2 (g) → CH2CHCHCH2 (g) + CH3CHCH2 (g)	Δ_rH°(0 K) = 0.88 ± 1.0 kcal/mol	Ruscic CBS-n
1.4	7652.5	CH3C(O)CHCH2 (g, trans) + CH2C(CH3)2 (g) → CH3C(O)CH3 (g) + CH2C(CH3)CHCH2 (g)	Δ_rH°(0 K) = -2.95 ± 0.85 kcal/mol	Ruscic W1RO
1.4	3998.1	CH2C(CH3)CHCH2 (g) + CH3CH3 (g) → CH2CHCHCH2 (g) + CH3CH2CH3 (g)	Δ_rH°(0 K) = 3.58 ± 1.1 kcal/mol	Ruscic G3X
1.3	7652.2	CH3C(O)CHCH2 (g, trans) + CH2C(CH3)2 (g) → CH3C(O)CH3 (g) + CH2C(CH3)CHCH2 (g)	Δ_rH°(0 K) = -2.96 ± 0.90 kcal/mol	Ruscic G4
1.3	7652.4	CH3C(O)CHCH2 (g, trans) + CH2C(CH3)2 (g) → CH3C(O)CH3 (g) + CH2C(CH3)CHCH2 (g)	Δ_rH°(0 K) = -2.95 ± 0.90 kcal/mol	Ruscic CBS-n
1.3	7652.1	CH3C(O)CHCH2 (g, trans) + CH2C(CH3)2 (g) → CH3C(O)CH3 (g) + CH2C(CH3)CHCH2 (g)	Δ_rH°(0 K) = -2.87 ± 0.90 kcal/mol	Ruscic G3X
1.0	7652.3	CH3C(O)CHCH2 (g, trans) + CH2C(CH3)2 (g) → CH3C(O)CH3 (g) + CH2C(CH3)CHCH2 (g)	Δ_rH°(0 K) = -2.86 ± 1.0 kcal/mol	Ruscic CBS-n
1.0	3998.3	CH2C(CH3)CHCH2 (g) + CH3CH3 (g) → CH2CHCHCH2 (g) + CH3CH2CH3 (g)	Δ_rH°(0 K) = 3.56 ± 1.3 kcal/mol	Ruscic CBS-n
0.9	3996.5	CH2C(CH3)CHCH2 (g) → 5 C (g) + 8 H (g)	Δ_rH°(0 K) = 1240.97 ± 1.50 kcal/mol	Ruscic W1RO
0.7	3996.4	CH2C(CH3)CHCH2 (g) → 5 C (g) + 8 H (g)	Δ_rH°(0 K) = 1240.93 ± 1.60 kcal/mol	Ruscic CBS-n

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH2C(CH3)CHCH2 (cr,l)

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
93.9	Isoprene	CH2C(CH3)CHCH2 (g)	96.27	75.75	± 0.66	kJ/mol	68.1170 ± 0.0040	78-79-5*0
18.7	3-Buten-2-one	CH3C(O)CHCH2 (g, trans)	-95.30	-111.54	± 0.85	kJ/mol	70.0898 ± 0.0032	78-94-4*1
18.7	3-Buten-2-one	CH3C(O)CHCH2 (g)	-95.30	-110.84	± 0.85	kJ/mol	70.0898 ± 0.0032	78-94-4*0
16.9	1,3-Butadiene	CH2CHCHCH2 (g)	125.61	111.14	± 0.29	kJ/mol	54.0904 ± 0.0032	106-99-0*0
14.7	Carbonic acid	C(O)(OH)2 (aq, undissoc)		-698.673	± 0.028	kJ/mol	62.0248 ± 0.0012	463-79-6*1000
13.8	n-Butane	CH3CH2CH2CH3 (g)	-98.25	-125.56	± 0.18	kJ/mol	58.1222 ± 0.0033	106-97-8*0
12.6	Propane	CH3CH2CH3 (g)	-82.73	-105.01	± 0.15	kJ/mol	44.0956 ± 0.0025	74-98-6*0
12.6	Water	H2O (cr,l)	-286.276	-285.804	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*500
12.6	Water	H2O (l)		-285.804	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*590
12.6	Oxonium	[H3O]+ (aq)		-285.804	± 0.022	kJ/mol	19.02267 ± 0.00037	13968-08-6*800

Most Influential reactions involving CH2C(CH3)CHCH2 (cr,l)

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
0.872	4002.3	CH2C(CH3)CHCH2 (cr,l) → CH2C(CH3)CHCH2 (g)	Δ_rH°(298.15 K) = 6.40 ± 0.06 kcal/mol	Bekkedahl 1936, as quoted by Cox 1970
0.177	4001.1	CH2C(CH3)CHCH2 (cr,l) + 7 O2 (g) → 5 CO2 (g) + 4 H2O (cr,l)	Δ_rH°(298.15 K) = -3158.5 ± 1.6 kJ/mol	Jessup 1938a, Fraser 1955
0.055	4002.2	CH2C(CH3)CHCH2 (cr,l) → CH2C(CH3)CHCH2 (g)	Δ_rH°(298.15 K) = 26.9 ± 1. kJ/mol	WinTable 2003, est unc
0.055	4002.1	CH2C(CH3)CHCH2 (cr,l) → CH2C(CH3)CHCH2 (g)	Δ_rH°(298.15 K) = 26.29 ± 1. kJ/mol	ThermoData 2004

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.