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].

Oxomethylium

Formula: [HCO]+ (g)
CAS RN: 17030-74-9
ATcT ID: 17030-74-9*0
SMILES: [CH+]=O
InChI: InChI=1S/CHO/c1-2/h1H/q+1
InChIKey: XPRMKTHGXOVKEH-UHFFFAOYSA-N
Hills Formula: C1H1O1+

2D Image:

[CH+]=O
Aliases: Oxomethylium; Methylidyneoxidanium; Oxomethylium ion; Oxomethylium cation; Oxomethylium ion (1+); Formylium; Formylium ion; Formylium cation; Formylium ion (1+); Formyl cation; Formyl ion (1+); Hydrogen carbonyl cation; Hydrogen carbonyl ion (1+); Hydrogen carbonyl monocation; [HCO]+; HCO+; [CHO]+; CHO+; [OCH]+; OCH+
Relative Molecular Mass: 29.01749 ± 0.00086

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
827.763827.179± 0.095kJ/mol

3D Image of [HCO]+ (g)

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Top contributors to the provenance of ΔfH° of [HCO]+ (g)

The 20 contributors listed below account only for 62.3% of the provenance of ΔfH° of [HCO]+ (g).
A total of 272 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
20.33098.11 [HCO]+ (g) → H+ (g) CO (g) ΔrH°(0 K) = 586.51 ± 0.2 kJ/molCzako 2008
10.23026.3 CO (g) H2 (g) → CH2O (g) ΔrH°(0 K) = 8.39 ± 0.28 kJ/molCzako 2009
3.03100.9 CO (g) [NH4]+ (g) → [HCO]+ (g) NH3 (g) ΔrH°(0 K) = 259.89 ± 0.3 kJ/molCzako 2008
2.93025.7 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.44 ± 0.25 kcal/molKarton 2006
2.93025.8 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.44 ± 0.25 kcal/molKarton 2006
2.53006.1 [CH2OH]+ (g) → CH2O (g) H+ (g) ΔrH°(0 K) = 704.98 ± 0.39 kJ/molCzako 2009
2.33091.9 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1132.68 ± 0.56 kJ/molHarding 2008
2.03025.6 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.52 ± 0.30 kcal/molKarton 2006
1.63028.1 CH2O (g) O2 (g) → CO2 (g) H2O (cr,l) ΔrH°(299.65 K) = -570.69 ± 0.40 (×1.756) kJ/molFletcher 1970, note std dev
1.51666.8 [NH4]+ (g) → NH3 (g) H+ (g) ΔrH°(0 K) = 846.40 ± 0.3 kJ/molCzako 2008
1.53091.7 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1133.05 ± 0.70 kJ/molHarding 2008
1.42286.9 C (graphite) CO2 (g) → 2 CO (g) ΔrG°(1165 K) = -33.545 ± 0.058 kJ/molSmith 1946, note COf, 3rd Law
1.33091.8 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1132.53 ± 0.74 kJ/molHarding 2008
1.23091.6 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1132.11 ± 0.75 (×1.022) kJ/molTajti 2004, est unc
1.23101.11 HCO (g) → H (g) CO (g) ΔrH°(0 K) = 60.2 ± 0.8 kJ/molMarenich 2003
1.13017.10 CH2O (g) → C (g) + 2 H (g) O (g) ΔrH°(0 K) = 1495.36 ± 0.80 kJ/molFeller 2018a
1.13025.4 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.37 ± 0.40 kcal/molBoese 2004
1.13025.5 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.52 ± 0.40 kcal/molKarton 2006
1.03091.12 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1132.50 ± 0.84 kJ/molHarding 2008
1.03091.10 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1132.87 ± 0.84 kJ/molHarding 2008

Top 10 species with enthalpies of formation correlated to the ΔfH° of [HCO]+ (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 Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass
ATcT ID
99.8 FormylHCO (g)[CH]=O41.38841.762± 0.094kJ/mol29.01804 ±
0.00086
2597-44-6*0
99.4 FormaldehydeCH2O (g, triplet)C=O196.008192.706± 0.094kJ/mol30.02598 ±
0.00087
50-00-0*1
99.4 FormaldehydeCH2O (g, ortho singlet)C=O-105.256-109.222± 0.094kJ/mol30.02598 ±
0.00087
50-00-0*22
99.4 FormaldehydeCH2O (g, para singlet)C=O-105.382-109.223± 0.094kJ/mol30.02598 ±
0.00087
50-00-0*21
99.4 FormaldehydeCH2O (g, singlet)C=O-105.382-109.223± 0.094kJ/mol30.02598 ±
0.00087
50-00-0*2
99.4 FormaldehydeCH2O (g)C=O-105.382-109.223± 0.094kJ/mol30.02598 ±
0.00087
50-00-0*0
98.1 Formaldehyde cation[CH2O]+ (g)C=[O+]944.859941.238± 0.096kJ/mol30.02543 ±
0.00087
54288-05-0*0
43.3 FormaldehydeCH2O (aq, unhydrol)C=O-165.65± 0.22kJ/mol30.02598 ±
0.00087
50-00-0*1000
22.7 HydroxymethyleneHCOH (g, trans)[CH]O112.70108.93± 0.27kJ/mol30.02598 ±
0.00087
19710-56-6*1
22.7 HydroxymethyleneHCOH (g)[CH]O112.70108.95± 0.27kJ/mol30.02598 ±
0.00087
19710-56-6*0

Most Influential reactions involving [HCO]+ (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
0.9993092.1 HCO (g) → [HCO]+ (g) ΔrH°(0 K) = 65735.9 ± 0.5 cm-1Mayer 1995, Foltynowicz 2001
0.4423100.9 CO (g) [NH4]+ (g) → [HCO]+ (g) NH3 (g) ΔrH°(0 K) = 259.89 ± 0.3 kJ/molCzako 2008
0.2302485.3 [C2H7]+ (g) CO (g) → [HCO]+ (g) CH3CH3 (g) ΔrG°(298.15 K) = 1.43 ± 0.3 kcal/molMackay 1981, 3rd Law, note unc5
0.2183098.11 [HCO]+ (g) → H+ (g) CO (g) ΔrH°(0 K) = 586.51 ± 0.2 kJ/molCzako 2008
0.1563122.4 [HCO]+ (g) → [COH]+ (g) ΔrH°(0 K) = 37.81 ± 0.5 kcal/molMartin 1993
0.1389715.7 [OS(OH)O]+ (g) CO (g) → OS(O)O (g) [HCO]+ (g) ΔrH°(0 K) = -0.27 ± 0.8 kcal/molRuscic W1RO
0.1231218.1 [HBrH]+ (g) CO (g) → [HCO]+ (g) HBr (g) ΔrH°(300 K) = -2.0 ± 2 kcal/molTichy 1989, 2nd Law, est unc
0.1193122.5 [HCO]+ (g) → [COH]+ (g) ΔrH°(0 K) = 13224 ± 200 cm-1Mladenovic 1998, est unc
0.1083122.3 [HCO]+ (g) → [COH]+ (g) ΔrH°(0 K) = 37.78 ± 0.6 kcal/molMartin 1993
0.0889715.4 [OS(OH)O]+ (g) CO (g) → OS(O)O (g) [HCO]+ (g) ΔrH°(0 K) = -0.15 ± 1.0 kcal/molRuscic G4
0.0793122.8 [HCO]+ (g) → [COH]+ (g) ΔrH°(0 K) = 38.12 ± 0.7 kcal/molGrunenberg 2003, Ruscic G3B3, est unc
0.0682385.2 [CH5]+ (g) CO (g) → [HCO]+ (g) CH4 (g) ΔrH°(441 K) = -11.5 ± 0.4 kcal/molSzulejko 1993, 2nd Law, note unc5
0.0619715.3 [OS(OH)O]+ (g) CO (g) → OS(O)O (g) [HCO]+ (g) ΔrH°(0 K) = -1.11 ± 1.2 kcal/molRuscic G3X
0.0613122.6 [HCO]+ (g) → [COH]+ (g) ΔrH°(0 K) = 37.66 ± 0.8 kcal/molYamaguchi 1994, est unc
0.0529715.6 [OS(OH)O]+ (g) CO (g) → OS(O)O (g) [HCO]+ (g) ΔrH°(0 K) = -1.23 ± 1.3 kcal/molRuscic CBS-n
0.0493107.2 HC(O)OH (g, syn) → [HCO]+ (g) OH (g) ΔrH°(0 K) = 12.81 ± 0.01 eVTraeger 1985, AE corr
0.0454750.2 HC(O)OH (g) → [HCO]+ (g) OH (g) ΔrH°(0 K) = 1235.7 ± 1.0 kJ/molShuman 2010a, Bomble 2006
0.0442385.1 [CH5]+ (g) CO (g) → [HCO]+ (g) CH4 (g) ΔrG°(441 K) = -8.6 ± 0.5 kcal/molSzulejko 1993, 3rd Law, note unc5
0.0422485.2 [C2H7]+ (g) CO (g) → [HCO]+ (g) CH3CH3 (g) ΔrG°(337 K) = 1.7 ± 0.7 kcal/molSzulejko 1993, 3rd Law, note unc5
0.0412001.1 [HONO]+ (g) CO (g) → [HCO]+ (g) ONO (g) ΔrG°(298.15 K) = -2 ± 2 kcal/molPolley 1984


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. 1.176 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.