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].

Hydroxyoxomethylium

Formula: [HOCO]+ (g)

CAS RN: 638-71-1

ATcT ID: 638-71-1*0

SMILES: O[C+]=O

InChI: InChI=1S/CHO2/c2-1-3/h(H,2,3)/q+1

InChIKey: CLJFDRKGHKJAKZ-UHFFFAOYSA-N

SMILES: C(=[OH+])=O

InChI: InChI=1S/CO2/c2-1-3/p+1

InChIKey: CURLTUGMZLYLDI-UHFFFAOYSA-O

Hills Formula: C1H1O2+

2D Image:

Aliases: [HOCO]+; Hydroxyoxomethylium; Hydroxy(oxo)methylium; Hydroxyoxomethylium ion; Hydroxyoxomethylium cation; Hydroxyoxomethylium ion (1+); Hydroxyformylium; Hydroxyformylium ion; Hydroxyformylium cation; Hydroxyformylium ion (1+); HOCO+; [OCOH]+; OCOH+; [C(O)OH]+; C(O)OH+; 196105-96-1; Hydroxyoxomethyl cation; Hydroxyoxomethyl ion (1+); (Oxomethylene)oxonium

Relative Molecular Mass: 45.0169 ± 0.0010

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
600.69	597.60	± 0.43	kJ/mol

3D Image of [HOCO]+ (g)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of [HOCO]+ (g)

The 20 contributors listed below account only for 62.2% of the provenance of Δ_fH° of [HOCO]+ (g).
A total of 75 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
14.6	4902.14	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 1187.3 ± 1.0 kJ/mol	Shuman 2010a
9.2	4902.2	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.316 ± 0.013 eV	Ruscic 1989
6.1	2385.2	[CH5]+ (g) + CO (g) → [HCO]+ (g) + CH4 (g)	Δ_rH°(441 K) = -11.5 ± 0.4 kcal/mol	Szulejko 1993, 2nd Law, note unc5
3.9	2385.1	[CH5]+ (g) + CO (g) → [HCO]+ (g) + CH4 (g)	Δ_rG°(441 K) = -8.6 ± 0.5 kcal/mol	Szulejko 1993, 3rd Law, note unc5
3.9	4902.4	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.30 ± 0.02 eV	Shuman 2010a, est unc
3.9	4902.6	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.31 ± 0.02 eV	Villem 1975, Akopyan 1976, AE corr
3.9	4902.1	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.30 ± 0.02 eV	Ruscic 1989
1.7	4902.5	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.29 ± 0.03 eV	Warneck 1974
1.5	2386.8	[CH5]+ (g) + H2O (g) → [H3O]+ (g) + CH4 (g)	Δ_rH°(0 K) = -34.21 ± 0.8 kcal/mol	Ruscic W1RO
1.4	2484.2	[C2H7]+ (g) + CH4 (g) → [CH5]+ (g) + CH3CH3 (g)	Δ_rG°(334 K) = 10.5 ± 0.7 kcal/mol	Szulejko 1993, 3rd Law, note unc5
1.4	2378.14	[CH5]+ (g) → CH4 (g) + H+ (g)	Δ_rH°(0 K) = 538.0 ± 3.5 kJ/mol	Kwan 2018, est unc
1.3	4903.8	[HOCO]+ (g) → CO2 (g) + H+ (g)	Δ_rH°(0 K) = 128.00 ± 0.90 kcal/mol	Ruscic W1RO
1.2	1891.3	[NNH]+ (g) + CO2 (g) → N2 (g) + [HOCO]+ (g)	Δ_rG°(561 K) = -12.6 ± 0.6 (×1.269) kcal/mol	Szulejko 1993, 3rd Law, note unc5
1.2	2378.8	[CH5]+ (g) → CH4 (g) + H+ (g)	Δ_rH°(0 K) = 129.28 ± 0.90 kcal/mol	Ruscic W1RO
1.1	2478.5	[C2H7]+ (g, bridged C2) + CH4 (g) → [CH5]+ (g) + CH3CH3 (g)	Δ_rH°(0 K) = 10.71 ± 0.8 kcal/mol	Ruscic W1RO
1.0	4879.13	HOCO (g, trans) → [HOCO]+ (g)	Δ_rH°(0 K) = 8.097 ± 0.040 eV	Ruscic W1RO
1.0	4880.8	HOCO (g, cis) → [HOCO]+ (g)	Δ_rH°(0 K) = 8.029 ± 0.040 eV	Ruscic W1RO
1.0	4903.10	[HOCO]+ (g) → CO2 (g) + H+ (g)	Δ_rH°(0 K) = 128.4 ± 1.0 kcal/mol	Komornicki 1992, note unc2
1.0	4904.1	[HCO]+ (g) + CO2 (g) → [HOCO]+ (g) + CO (g)	Δ_rH°(0 K) = 12.0 ± 1.0 kcal/mol	Komornicki 1992, est unc
1.0	2378.12	[CH5]+ (g) → CH4 (g) + H+ (g)	Δ_rH°(0 K) = 129.4 ± 1 kcal/mol	Muller 1997

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [HOCO]+ (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
96.8	Methanium	[CH5]+ (g)	921.99	911.75	± 0.44	kJ/mol	17.04985 ± 0.00087	15135-49-6*0
23.9	Formic acid	HC(O)OH (g, syn)	-371.03	-378.35	± 0.21	kJ/mol	46.0254 ± 0.0010	64-18-6*1
23.9	Formic acid	HC(O)OH (g)	-371.03	-378.33	± 0.21	kJ/mol	46.0254 ± 0.0010	64-18-6*0
20.0	Formic acid cation	[HC(O)OH]+ (g, syn)	721.94	714.86	± 0.25	kJ/mol	46.0248 ± 0.0010	50614-05-6*1
20.0	Formic acid cation	[HC(O)OH]+ (g)	721.94	715.41	± 0.25	kJ/mol	46.0248 ± 0.0010	50614-05-6*0
15.8	Formic acid	HC(O)OH (cr,l)	-431.50	-424.67	± 0.20	kJ/mol	46.0254 ± 0.0010	64-18-6*500
12.4	Formic acid	HC(O)OH (g, anti)	-354.70	-361.80	± 0.37	kJ/mol	46.0254 ± 0.0010	64-18-6*2
11.4	Ethanium	[C2H7]+ (g, bridged C2)	874.37	858.11	± 0.61	kJ/mol	31.0764 ± 0.0017	24669-33-8*1
11.4	Ethanium	[C2H7]+ (g)	874.37	858.13	± 0.61	kJ/mol	31.0764 ± 0.0017	24669-33-8*0
10.6	Diazynium	[NNH]+ (g)	1042.57	1038.96	± 0.67	kJ/mol	29.02087 ± 0.00016	12357-66-3*0

Most Influential reactions involving [HOCO]+ (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
0.252	2383.5	[CH5]+ (g) + CO2 (g) → [HOCO]+ (g) + CH4 (g)	Δ_rG°(296 K) = 7.92 ± 0.20 kJ/mol	Bohme 1973a, 3rd Law, note unc
0.229	2383.7	[CH5]+ (g) + CO2 (g) → [HOCO]+ (g) + CH4 (g)	Δ_rG°(296 K) = 7.82 ± 0.21 kJ/mol	Hemsworth 1973, 3rd Law, note unc
0.208	2383.6	[CH5]+ (g) + CO2 (g) → [HOCO]+ (g) + CH4 (g)	Δ_rG°(296 K) = 7.72 ± 0.22 kJ/mol	Bohme 1973a, 3rd Law, note unc
0.185	4902.14	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 1187.3 ± 1.0 kJ/mol	Shuman 2010a
0.161	2383.4	[CH5]+ (g) + CO2 (g) → [HOCO]+ (g) + CH4 (g)	Δ_rG°(296 K) = 7.78 ± 0.25 kJ/mol	Bohme 1973a, 3rd Law, note unc
0.117	4902.2	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.316 ± 0.013 eV	Ruscic 1989
0.087	2383.3	[CH5]+ (g) + CO2 (g) → [HOCO]+ (g) + CH4 (g)	Δ_rG°(296 K) = 7.86 ± 0.34 kJ/mol	Bohme 1973a, 3rd Law, note unc
0.074	4924.8	[HOCO]+ (g) → [HC(O)O]+ (g)	Δ_rH°(0 K) = 100.30 ± 1.2 kcal/mol	Ruscic W1RO
0.063	4924.4	[HOCO]+ (g) → [HC(O)O]+ (g)	Δ_rH°(0 K) = 99.39 ± 1.3 kcal/mol	Ruscic G4
0.056	1891.3	[NNH]+ (g) + CO2 (g) → N2 (g) + [HOCO]+ (g)	Δ_rG°(561 K) = -12.6 ± 0.6 (×1.269) kcal/mol	Szulejko 1993, 3rd Law, note unc5
0.054	4924.3	[HOCO]+ (g) → [HC(O)O]+ (g)	Δ_rH°(0 K) = 99.96 ± 1.4 kcal/mol	Ruscic G3X
0.050	4924.7	[HOCO]+ (g) → [HC(O)O]+ (g)	Δ_rH°(0 K) = 98.15 ± 1.2 (×1.215) kcal/mol	Ruscic CBS-n
0.049	4902.4	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.30 ± 0.02 eV	Shuman 2010a, est unc
0.049	4902.1	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.30 ± 0.02 eV	Ruscic 1989
0.049	4902.6	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.31 ± 0.02 eV	Villem 1975, Akopyan 1976, AE corr
0.041	4924.6	[HOCO]+ (g) → [HC(O)O]+ (g)	Δ_rH°(0 K) = 99.57 ± 1.6 kcal/mol	Ruscic CBS-n
0.038	1891.4	[NNH]+ (g) + CO2 (g) → N2 (g) + [HOCO]+ (g)	Δ_rH°(561 K) = -10.7 ± 0.6 (×1.542) kcal/mol	Szulejko 1993, 2nd Law, note unc5
0.036	1891.1	[NNH]+ (g) + CO2 (g) → N2 (g) + [HOCO]+ (g)	Δ_rG°(800 K) = -59.61 ± 3.93 kJ/mol	Bohme 1980, 3rd Law, note unc
0.032	1891.2	[NNH]+ (g) + CO2 (g) → N2 (g) + [HOCO]+ (g)	Δ_rH°(0 K) = -12.1 ± 1.0 kcal/mol	Komornicki 1992, est unc
0.029	9378.1	[XeH]+ (g) + CO2 (g) → [HOCO]+ (g) + Xe (g)	Δ_rG°(800 K) = -30.29 ± 3.58 (×1.542) kJ/mol	Bohme 1980, 3rd Law, note unc

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.