Selected ATcT [1, 2] enthalpy of formation based on version 1.122r of the Thermochemical Network [3]

This version of ATcT results was generated from an expansion of version 1.122q [4, 5] to include a non-rigid rotor anharmonic oscillator (NRRAO) partition function for hydroxymethyl [6], as well as data on 42 additional species, some of which are related to soot formation mechanisms.
Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass
ATcT ID
PropynylideneHCCCH (g, triplet)[CH]=C=[CH]543.45546.45± 0.65kJ/mol38.0480 ±
0.0024
67152-18-5*1
1-Cyclopropene-1,2-diylCH2(CC) (g)C1[C]=[C]1791.0790.6± 1.5kJ/mol38.0480 ±
0.0024
202744-75-0*0

Reaction Enthalpy

 HCCCH (g, triplet) → CH2(CC) (g)
 HCCCH (g, triplet) → CH2(CC) (g)
 [CH]=C=[CH] → C1[C]=[C]1


Note: The listed uncertainity of the reaction enthalpy is computed using the full covariance matrix.

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 21st 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. 1.122r of the Thermochemical Network, Argonne National Laboratory, Lemont, Illinois 2021 [DOI: 10.17038/CSE/1822363]; available at ATcT.anl.gov
4   D. Feller, D. H. Bross, and B. Ruscic,
Enthalpy of Formation of C2H2O4 (Oxalic Acid) from High-Level Calculations and the Active Thermochemical Tables Approach.
J. Phys. Chem. A 123, 3481-3496 (2019) [DOI: 10.1021/acs.jpca.8b12329]
5   B. K. Welch, R. Dawes, D. H. Bross, and B. Ruscic,
An Automated Thermochemistry Protocol Based on Explicitly Correlated Coupled-Cluster Theory: The Methyl and Ethyl Peroxy Families.
J. Phys. Chem. A 123, 5673-5682 (2019) [DOI: 10.1021/acs.jpca.8b12329]
6   D. H. Bross, H.-G. Yu, L. B. Harding, and B. Ruscic,
Active Thermochemical Tables: The Partition Function of Hydroxymethyl (CH2OH) Revisited.
J. Phys. Chem. A 123, 4212-4231 (2019) [DOI: 10.1021/acs.jpca.9b02295]
7   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]

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 [7]).
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.