Selected ATcT [1, 2] enthalpy of formation based on version 1.124 of the Thermochemical Network [3]

This version of ATcT results was generated by additional expansion of version 1.122x [4] to include additional information relevant to the study of thermophysical and thermochemical properties of CH2 and CH3 using nonrigid rotor anharmonic oscillator (NRRAO) partition functions [5], the development and benchmarking of a state-of-the-art computational approach that aims to reproduce total atomization energies of small molecules within 10–15 cm^-1 [6], as well as the study of the reversible reaction C₂H₃ + H₂ ⇌ C₂H₄ + H ⇌ C₂H₅ [7]

Hydroxymethylene

Formula: HCOH (g, gauche triplet)

CAS RN: 19710-56-6

ATcT ID: 19710-56-6*3

SMILES: [CH]O

InChI: InChI=1S/CH2O/c1-2/h1-2H

InChIKey: UUOIGPDTLYBNGY-UHFFFAOYSA-N

Hills Formula: C1H2O1

2D Image:

Aliases: HCOH; Hydroxymethylene; Hydroxymethylidene; Hydroxycarbene; CHOH; HOCH

Relative Molecular Mass: 30.02598 ± 0.00087

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
219.3	216.4	± 1.1	kJ/mol

3D Image of HCOH (g, gauche triplet)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of HCOH (g, gauche triplet)

The 20 contributors listed below account only for 61.7% of the provenance of Δ_fH° of HCOH (g, gauche triplet).
A total of 44 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
6.2	2910.9	HCOH (g, gauche triplet) → C (g) + O (g) + 2 H (g)	Δ_rH°(0 K) = 279.95 ± 1 kcal/mol	Matus 2006
6.0	2927.11	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 24.8 ± 1.0 kcal/mol	Hwang 1999, est unc
4.2	2927.8	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8811 ± 420 cm-1	Ruscic W1RO
3.6	2927.4	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8970 ± 450 cm-1	Ruscic G4
3.5	2927.7	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8735 ± 455 cm-1	Ruscic CBS-n
3.0	2927.3	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8900 ± 490 cm-1	Ruscic G3X
2.8	2942.5	CO (g, triplet) + H2 (g) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -59.63 ± 1.50 kcal/mol	Ruscic W1RO
2.7	2910.8	HCOH (g, gauche triplet) → C (g) + O (g) + 2 H (g)	Δ_rH°(0 K) = 280.46 ± 1.50 kcal/mol	Ruscic W1RO
2.7	2941.8	CH2O (g) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 77.37 ± 1.50 kcal/mol	Parthiban 2001
2.6	2913.8	HCOH (g, gauche triplet) → [HCOH]+ (g, gauche quartet)	Δ_rH°(0 K) = 13.097 ± 0.040 eV	Ruscic W1RO
2.5	2956.5	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -53.61 ± 1.2 kcal/mol	Ruscic W1RO
2.4	2942.4	CO (g, triplet) + H2 (g) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -58.88 ± 1.60 kcal/mol	Ruscic CBS-n
2.4	2942.2	CO (g, triplet) + H2 (g) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -57.98 ± 1.60 kcal/mol	Ruscic G4
2.4	2910.4	HCOH (g, gauche triplet) → C (g) + O (g) + 2 H (g)	Δ_rH°(0 K) = 280.14 ± 1.60 kcal/mol	Ruscic G4
2.4	2910.7	HCOH (g, gauche triplet) → C (g) + O (g) + 2 H (g)	Δ_rH°(0 K) = 280.26 ± 1.60 kcal/mol	Ruscic CBS-n
2.4	2941.4	CH2O (g) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 77.97 ± 1.60 kcal/mol	Ruscic G4
2.4	2941.7	CH2O (g) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 77.60 ± 1.60 kcal/mol	Ruscic CBS-n
2.3	2927.6	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 9065 ± 560 cm-1	Ruscic CBS-n
2.1	2956.4	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -53.71 ± 1.3 kcal/mol	Ruscic CBS-n
2.1	2956.2	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -53.60 ± 1.3 kcal/mol	Ruscic G4

Top 10 species with enthalpies of formation correlated to the Δ_fH° of HCOH (g, gauche triplet)

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
23.5	Hydroxymethylene cation	[HCOH]+ (g, gauche quartet)	1482.1	1479.4	± 1.9	kJ/mol	30.02543 ± 0.00087	135395-06-1*3
20.7	Aquacarbon	H2OC (g, triplet)	442.7	441.1	± 1.3	kJ/mol	30.02598 ± 0.00087	81434-73-3*1
20.7	Hydroxymethylene anion	[HCOH]- (g, gauche quartet)	334.0	334.8	± 2.1	kJ/mol	30.02653 ± 0.00087	207914-87-2*3
7.9	Hydroxymethylene	HCOH (g, trans)	112.68	108.91	± 0.27	kJ/mol	30.02598 ± 0.00087	19710-56-6*1
7.9	Hydroxymethylene	HCOH (g)	112.68	108.92	± 0.27	kJ/mol	30.02598 ± 0.00087	19710-56-6*0
6.5	Hydroxymethylene cation	[HCOH]+ (g)	971.9	968.3	± 1.4	kJ/mol	30.02543 ± 0.00087	135395-06-1*0
6.5	Hydroxymethylene cation	[HCOH]+ (g, trans)	971.9	968.2	± 1.4	kJ/mol	30.02543 ± 0.00087	135395-06-1*1
6.0	Hydroxymethylene	HCOH (g, cis)	131.10	127.36	± 0.29	kJ/mol	30.02598 ± 0.00087	19710-56-6*2
5.8	Hydroxymethylene anion	[HCOH]- (g, trans)	147.2	144.1	± 1.6	kJ/mol	30.02653 ± 0.00087	207914-87-2*1
5.8	Hydroxymethylene anion	[HCOH]- (g)	147.2	144.2	± 1.6	kJ/mol	30.02653 ± 0.00087	207914-87-2*0

Most Influential reactions involving HCOH (g, gauche triplet)

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
0.235	2913.8	HCOH (g, gauche triplet) → [HCOH]+ (g, gauche quartet)	Δ_rH°(0 K) = 13.097 ± 0.040 eV	Ruscic W1RO
0.190	2916.6	[HCOH]- (g, gauche quartet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -1.185 ± 0.050 eV	Ruscic W1RO
0.128	2916.4	[HCOH]- (g, gauche quartet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -1.202 ± 0.061 eV	Ruscic G4
0.081	2956.5	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -53.61 ± 1.2 kcal/mol	Ruscic W1RO
0.070	2913.4	HCOH (g, gauche triplet) → [HCOH]+ (g, gauche quartet)	Δ_rH°(0 K) = 13.071 ± 0.073 eV	Ruscic G4
0.069	2956.2	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -53.60 ± 1.3 kcal/mol	Ruscic G4
0.069	2956.4	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -53.71 ± 1.3 kcal/mol	Ruscic CBS-n
0.066	2913.7	HCOH (g, gauche triplet) → [HCOH]+ (g, gauche quartet)	Δ_rH°(0 K) = 13.111 ± 0.075 eV	Ruscic CBS-n
0.066	2916.3	[HCOH]- (g, gauche quartet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -1.199 ± 0.085 eV	Ruscic G3X
0.064	2927.11	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 24.8 ± 1.0 kcal/mol	Hwang 1999, est unc
0.063	2910.9	HCOH (g, gauche triplet) → C (g) + O (g) + 2 H (g)	Δ_rH°(0 K) = 279.95 ± 1 kcal/mol	Matus 2006
0.060	2956.1	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -53.06 ± 1.4 kcal/mol	Ruscic G3X
0.056	2916.5	[HCOH]- (g, gauche quartet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -1.211 ± 0.092 eV	Ruscic CBS-n
0.046	2956.3	H2OC (g, triplet) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = -54.02 ± 1.6 kcal/mol	Ruscic CBS-n
0.044	2927.8	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8811 ± 420 cm-1	Ruscic W1RO
0.043	2913.3	HCOH (g, gauche triplet) → [HCOH]+ (g, gauche quartet)	Δ_rH°(0 K) = 13.067 ± 0.093 eV	Ruscic G3X
0.039	2927.4	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8970 ± 450 cm-1	Ruscic G4
0.038	2913.6	HCOH (g, gauche triplet) → [HCOH]+ (g, gauche quartet)	Δ_rH°(0 K) = 13.148 ± 0.099 eV	Ruscic CBS-n
0.038	2927.7	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8735 ± 455 cm-1	Ruscic CBS-n
0.032	2927.3	HCOH (g, trans) → HCOH (g, gauche triplet)	Δ_rH°(0 K) = 8900 ± 490 cm-1	Ruscic G3X

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. 1.124 of the Thermochemical Network, Argonne National Laboratory, Lemont, Illinois 2022; available at ATcT.anl.gov [DOI: 10.17038/CSE/1885923]
4		Y. Ren, L. Zhou, A. Mellouki, V. Daële, M. Idir, S. S. Brown, B. Ruscic, Robert S. Paton, M. R. McGillen, and A. R. Ravishankara, Reactions of NO3 with Aromatic Aldehydes: Gas-Phase Kinetics and Insights into the Mechanism of the Reaction. Atmos. Chem. Phys. 21, 13537-13551 (2021) [DOI: 10.5194/acp2021-228]
5		B. Ruscic and D. H. Bross, Active Thermochemical Tables: The Thermophysical and Thermochemical Properties of Methyl, CH3, and Methylene, CH2, Corrected for Nonrigid Rotor and Anharmonic Oscillator Effects. Mol. Phys. e1969046 (2021) [DOI: 10.1080/00268976.2021.1969046]
6		J. H. Thorpe, J. L. Kilburn, D. Feller, P. B. Changala, D. H. Bross, B. Ruscic, and J. F. Stanton, Elaborated Thermochemical Treatment of HF, CO, N2, and H2O: Insight into HEAT and Its Extensions J. Chem. Phys. 155, 184109 (2021) [DOI: 10.1063/5.0069322]
7		T. L. Nguyen, D. H. Bross, B. Ruscic, G. B. Ellison, and J. F. Stanton, Mechanism, Thermochemistry, and Kinetics of the Reversible Reactions: C2H3 + H2 ⇌ C2H4 + H ⇌ C2H5. Faraday Discuss. , (Advance Article) (2022) [DOI: 10.1039/D1FD00124H]
8		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]
9		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 [8,9]).
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.