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].

Formic acid

Formula: HC(O)OH (g, syn)

CAS RN: 64-18-6

ATcT ID: 64-18-6*1

SMILES: C(=O)O

InChI: InChI=1S/CH2O2/c2-1-3/h1H,(H,2,3)

InChIKey: BDAGIHXWWSANSR-UHFFFAOYSA-N

Hills Formula: C1H2O2

2D Image:

Aliases: HC(O)OH; Formic acid; Hydrogen carboxylic acid; Methanoic acid; HCOOH; OCHOH; O=CH-OH; H(C=O)OH; Formylic acid; Aminic acid

Relative Molecular Mass: 46.0254 ± 0.0010

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
-371.03	-378.35	± 0.21	kJ/mol

3D Image of HC(O)OH (g, syn)

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Top contributors to the provenance of Δ_fH° of HC(O)OH (g, syn)

The 20 contributors listed below account only for 64.3% of the provenance of Δ_fH° of HC(O)OH (g, syn).
A total of 226 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
16.3	4751.2	HC(O)OH (cr,l) + 1/2 O2 (g) → CO2 (g) + H2O (cr,l)	Δ_rH°(298.15 K) = -60.807 ± 0.074 kcal/mol	Lebedeva 1964
11.3	4751.1	HC(O)OH (cr,l) + 1/2 O2 (g) → CO2 (g) + H2O (cr,l)	Δ_rH°(298.15 K) = -60.851 ± 0.089 kcal/mol	Sinke 1959
10.8	4752.1	HC(O)OH (cr,l) → HC(O)OH (g)	Δ_rH°(298.15 K) = 46.30 ± 0.23 kJ/mol	Majer 1985
3.8	3107.2	HC(O)OH (g, syn) → [HCO]+ (g) + OH (g)	Δ_rH°(0 K) = 12.81 ± 0.01 eV	Traeger 1985, AE corr
3.6	4750.2	HC(O)OH (g) → [HCO]+ (g) + OH (g)	Δ_rH°(0 K) = 1235.7 ± 1.0 kJ/mol	Shuman 2010a, Bomble 2006
3.5	4752.2	HC(O)OH (cr,l) → HC(O)OH (g)	Δ_rH°(298.15 K) = 46.15 ± 0.40 kJ/mol	NBS Tables 1989
2.5	4726.3	HC(O)OH (g, syn) → C (g) + 2 H (g) + 2 O (g)	Δ_rH°(0 K) = 479.81 ± 0.30 kcal/mol	Karton 2011
2.2	4752.3	HC(O)OH (cr,l) → HC(O)OH (g)	Δ_rH°(298.15 K) = 46.3 ± 0.5 kJ/mol	Konicek 1970
1.5	3137.6	C(O)(OH)2 (g, cis-cis) + CH2O (g) → 2 HC(O)OH (g, syn)	Δ_rH°(0 K) = -34.26 ± 2.0 kJ/mol	Klippenstein 2017
1.4	4725.10	HC(O)OH (g, syn) → C (g) + 2 H (g) + 2 O (g)	Δ_rH°(0 K) = 480.1 ± 0.4 kcal/mol	Feller 2003c
1.0	4806.11	CH2(OO) (g) → HC(O)OH (g, syn)	Δ_rH°(0 K) = -90.89 ± 0.25 kcal/mol	Karton 2011
1.0	4902.14	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 1187.3 ± 1.0 kJ/mol	Shuman 2010a
0.9	4740.1	CH4 (g) + 2 H2O (g) → HC(O)OH (g, syn) + 3 H2 (g)	Δ_rH°(0 K) = 173.33 ± 2.00 kJ/mol	Klippenstein 2017
0.7	4726.2	HC(O)OH (g, syn) → C (g) + 2 H (g) + 2 O (g)	Δ_rH°(0 K) = 479.82 ± 0.56 kcal/mol	Karton 2011
0.6	4902.2	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.316 ± 0.013 eV	Ruscic 1989
0.5	4798.11	CH2(OO) (g) → C (g) + 2 H (g) + 2 O (g)	Δ_rH°(0 K) = 388.92 ± 0.30 kcal/mol	Karton 2011
0.5	3138.11	C(O)(OH)2 (g, cis-cis) → CO2 (g) + H2O (g)	Δ_rH°(0 K) = -30.14 ± 2.0 kJ/mol	Klippenstein 2017
0.4	3132.1	CH4 (g) + 3 H2O (g) → C(O)(OH)2 (g, cis-cis) + 4 H2 (g)	Δ_rH°(0 K) = 181.13 ± 2.0 kJ/mol	Klippenstein 2017
0.4	3137.5	C(O)(OH)2 (g, cis-cis) + CH2O (g) → 2 HC(O)OH (g, syn)	Δ_rH°(0 K) = -8.03 ± 0.85 kcal/mol	Ruscic W1RO
0.4	3107.1	HC(O)OH (g, syn) → [HCO]+ (g) + OH (g)	Δ_rH°(0 K) = 12.84 ± 0.03 eV	Matthews 1969, AE corr

Top 10 species with enthalpies of formation correlated to the Δ_fH° of HC(O)OH (g, syn)

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
100.0	Formic acid	HC(O)OH (g)	-371.03	-378.33	± 0.21	kJ/mol	46.0254 ± 0.0010	64-18-6*0
83.5	Formic acid cation	[HC(O)OH]+ (g, syn)	721.94	714.86	± 0.25	kJ/mol	46.0248 ± 0.0010	50614-05-6*1
83.5	Formic acid cation	[HC(O)OH]+ (g)	721.94	715.41	± 0.25	kJ/mol	46.0248 ± 0.0010	50614-05-6*0
65.8	Formic acid	HC(O)OH (cr,l)	-431.50	-424.67	± 0.20	kJ/mol	46.0254 ± 0.0010	64-18-6*500
51.8	Formic acid	HC(O)OH (g, anti)	-354.70	-361.80	± 0.37	kJ/mol	46.0254 ± 0.0010	64-18-6*2
28.8	Formic acid	HC(O)OH (aq, undissoc)		-425.38	± 0.45	kJ/mol	46.0254 ± 0.0010	64-18-6*1000
28.8	Formic acid	HC(O)OH (aq)		-425.48	± 0.45	kJ/mol	46.0254 ± 0.0010	64-18-6*800
28.8	Formate	[HC(O)O]- (aq)		-425.48	± 0.45	kJ/mol	45.0180 ± 0.0010	71-47-6*800
27.5	Carbonic acid	C(O)(OH)2 (g, cis-cis)	-602.29	-612.46	± 0.55	kJ/mol	62.0248 ± 0.0012	463-79-6*1
27.5	Carbonic acid	C(O)(OH)2 (g)	-602.29	-611.60	± 0.55	kJ/mol	62.0248 ± 0.0012	463-79-6*0

Most Influential reactions involving HC(O)OH (g, syn)

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
1.000	4741.1	HC(O)OH (g) → HC(O)OH (g, syn)	Δ_rH°(0 K) = 0.000 ± 0.000 cm-1	triv, Gurvich TPIS, Ruscic G3B3
0.774	4744.1	HC(O)OH (g, syn) → HC(O)OH (g, anti)	Δ_rH°(0 K) = 1365 ± 30 cm-1	Hocking 1976, Gurvich TPIS
0.478	4728.2	HC(O)OH (g, syn) → [HC(O)OH]+ (g, syn)	Δ_rH°(0 K) = 11.329 ± 0.002 eV	Bell 1975
0.311	4728.1	HC(O)OH (g, syn) → [HC(O)OH]+ (g, syn)	Δ_rH°(0 K) = 91370 ± 20 cm-1	Price 1937, est unc
0.247	4806.11	CH2(OO) (g) → HC(O)OH (g, syn)	Δ_rH°(0 K) = -90.89 ± 0.25 kcal/mol	Karton 2011
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
0.169	4728.8	HC(O)OH (g, syn) → [HC(O)OH]+ (g, syn)	Δ_rH°(0 K) = 11.3246 ± 0.0020 (×1.682) eV	Leach 2003, Schwell 2001
0.143	5289.6	CH3C(O)OH (g, syn) + HOCO (g, trans) → CH3C(O)O (g, 2A") + HC(O)OH (g, syn)	Δ_rH°(0 K) = 45.92 ± 2.00 kJ/mol	Klippenstein 2017
0.133	4733.8	[HC(O)OH]- (g, syn) → HC(O)OH (g, syn)	Δ_rH°(0 K) = -1.204 ± 0.050 eV	Ruscic W1RO
0.117	4902.2	HC(O)OH (g, syn) → [HOCO]+ (g) + H (g)	Δ_rH°(0 K) = 12.316 ± 0.013 eV	Ruscic 1989
0.110	3148.6	HC(O)OOH (g, cis) + CH3OH (g) → HC(O)OH (g, syn) + CH3OOH (g)	Δ_rH°(0 K) = -16.39 ± 2.0 kJ/mol	Klippenstein 2017
0.098	3147.6	HC(O)OOH (g, cis) + H2O (g) → HC(O)OH (g, syn) + HOOH (g)	Δ_rH°(0 K) = 17.86 ± 2.0 kJ/mol	Klippenstein 2017
0.096	4806.10	CH2(OO) (g) → HC(O)OH (g, syn)	Δ_rH°(0 K) = -91.10 ± 0.40 kcal/mol	Karton 2011
0.095	5274.8	HC(O)OCH3 (g, syn) + HOCO (g, trans) → CH3OCO (g, anti-staggered) + HC(O)OH (g, syn)	Δ_rH°(0 K) = 1.11 ± 0.85 kcal/mol	Ruscic W1RO
0.092	4730.5	HC(O)OH (g, syn) → [HC(O)OH]+ (g, anti)	Δ_rH°(0 K) = 11.362 ± 0.040 eV	Ruscic W1RO
0.089	4733.4	[HC(O)OH]- (g, syn) → HC(O)OH (g, syn)	Δ_rH°(0 K) = -1.175 ± 0.061 eV	Ruscic G4
0.085	5274.4	HC(O)OCH3 (g, syn) + HOCO (g, trans) → CH3OCO (g, anti-staggered) + HC(O)OH (g, syn)	Δ_rH°(0 K) = 0.74 ± 0.90 kcal/mol	Ruscic G4
0.085	5274.7	HC(O)OCH3 (g, syn) + HOCO (g, trans) → CH3OCO (g, anti-staggered) + HC(O)OH (g, syn)	Δ_rH°(0 K) = 1.21 ± 0.90 kcal/mol	Ruscic CBS-n
0.085	5274.3	HC(O)OCH3 (g, syn) + HOCO (g, trans) → CH3OCO (g, anti-staggered) + HC(O)OH (g, syn)	Δ_rH°(0 K) = 1.05 ± 0.90 kcal/mol	Ruscic G3X
0.085	3137.6	C(O)(OH)2 (g, cis-cis) + CH2O (g) → 2 HC(O)OH (g, syn)	Δ_rH°(0 K) = -34.26 ± 2.0 kJ/mol	Klippenstein 2017

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.