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 nonrigid 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 
Δ_{f}H°(0 K) 
Δ_{f}H°(298.15 K) 
Uncertainty 
Units 
Relative Molecular Mass 
ATcT ID 
Ketenyl anion  [HCCO] (g)   48.47  47.54  ± 0.82  kJ/mol  41.0293 ± 0.0016  64066019*0 

Representative Geometry of [HCCO] (g) 

spin ON spin OFF 

Top contributors to the provenance of Δ_{f}H° of [HCCO] (g)The 9 contributors listed below account for 80.3% of the provenance of Δ_{f}H° of [HCCO] (g).
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.


Top 10 species with enthalpies of formation correlated to the Δ_{f}H° of [HCCO] (g) 
Please note: The correlation coefficients are obtained by renormalizing the offdiagonal 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 anticorrelated species, and 0 representing perfectly uncorrelated species.

Correlation Coefficent (%)  Species Name  Formula  Image  Δ_{f}H°(0 K)  Δ_{f}H°(298.15 K)  Uncertainty  Units  Relative Molecular Mass  ATcT ID  59.0  Ketenyl  HCCO (g)   177.06  178.16  ± 0.55  kJ/mol  41.0287 ± 0.0016  51095159*0  11.0  Hydroxyoxoethenyl  HOCCO (g)   24.3  22.5  ± 1.8  kJ/mol  57.0281 ± 0.0017  702699396*0  8.8  Ketene  CH2CO (g, singlet)   45.35  48.47  ± 0.11  kJ/mol  42.0367 ± 0.0016  463514*2  8.8  Ketene  CH2CO (g)   45.35  48.47  ± 0.11  kJ/mol  42.0367 ± 0.0016  463514*0  8.8  Ketene cation  [CH2CO]+ (g)   882.22  879.05  ± 0.11  kJ/mol  42.0361 ± 0.0016  64999162*0  8.6  Oxoethenylium  [HCCO]+ (g)   1139.7  1142.4  ± 2.1  kJ/mol  41.0282 ± 0.0016  92056638*0  8.3  Methylene  CH2 (g, singlet)   428.72  429.13  ± 0.11  kJ/mol  14.02658 ± 0.00081  2465567*2  7.7  Methylene  CH2 (g, triplet)   391.060  391.617  ± 0.097  kJ/mol  14.02658 ± 0.00081  2465567*1  7.7  Methylene  CH2 (g)   391.060  391.617  ± 0.097  kJ/mol  14.02658 ± 0.00081  2465567*0  7.3  Methyliumyl  [CH2]+ (g)   1393.19  1394.05  ± 0.11  kJ/mol  14.02603 ± 0.00081  15091722*0 

Most Influential reactions involving [HCCO] (g)Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.



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, 99799997 (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, 561570 (2005)
[DOI: 10.1088/17426596/16/1/078]

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 HighLevel Calculations and the Active Thermochemical Tables Approach.
J. Phys. Chem. A 123, 34813496 (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 CoupledCluster Theory: The Methyl and Ethyl Peroxy Families.
J. Phys. Chem. A 123, 56735682 (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, 42124231 (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, 10971101 (2014)
[DOI: 10.1002/qua.24605]

