Selected ATcT [1, 2] enthalpy of formation based on version 1.148 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.140 to include species relevant to a recent study of the role of atmospheric methanediol[4].

Formyl

Formula: HCO (g)

CAS RN: 2597-44-6

ATcT ID: 2597-44-6*0

SMILES: [CH]=O

SMILES: [CH-]#[O+]

InChI: InChI=1S/CHO/c1-2/h1H

InChIKey: CFHIDWOYWUOIHU-UHFFFAOYSA-N

Hills Formula: C1H1O1

2D Image:

Aliases: HCO; Formyl; Carbonyl; Formyl radical; Carbon hydride oxide; Oxomethyl; Hydrogen carbonyl; CHO; OCH; HC=O

Relative Molecular Mass: 29.01804 ± 0.00086

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
41.390	41.764	± 0.095	kJ/mol

3D Image of HCO (g)

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Top contributors to the provenance of Δ_fH° of HCO (g)

The 20 contributors listed below account only for 62.4% of the provenance of Δ_fH° of HCO (g).
A total of 270 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
20.3	3012.11	[HCO]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 586.51 ± 0.2 kJ/mol	Czako 2008
10.3	2940.3	CO (g) + H2 (g) → CH2O (g)	Δ_rH°(0 K) = 8.39 ± 0.28 kJ/mol	Czako 2009
3.0	3014.9	CO (g) + [NH4]+ (g) → [HCO]+ (g) + NH3 (g)	Δ_rH°(0 K) = 259.89 ± 0.3 kJ/mol	Czako 2008
2.9	2939.7	2 CH2O (g) → CH4 (g) + CO2 (g)	Δ_rH°(0 K) = -59.44 ± 0.25 kcal/mol	Karton 2006
2.9	2939.8	2 CH2O (g) → CH4 (g) + CO2 (g)	Δ_rH°(0 K) = -59.44 ± 0.25 kcal/mol	Karton 2006
2.5	2920.1	[CH2OH]+ (g) → CH2O (g) + H+ (g)	Δ_rH°(0 K) = 704.98 ± 0.39 kJ/mol	Czako 2009
2.4	3005.9	HCO (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 1132.68 ± 0.56 kJ/mol	Harding 2008
2.0	2939.6	2 CH2O (g) → CH4 (g) + CO2 (g)	Δ_rH°(0 K) = -59.52 ± 0.30 kcal/mol	Karton 2006
1.5	2942.1	CH2O (g) + O2 (g) → CO2 (g) + H2O (cr,l)	Δ_rH°(299.65 K) = -570.69 ± 0.40 (×1.795) kJ/mol	Fletcher 1970, note std dev
1.5	1650.8	[NH4]+ (g) → NH3 (g) + H+ (g)	Δ_rH°(0 K) = 846.40 ± 0.3 kJ/mol	Czako 2008
1.5	3005.7	HCO (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 1133.05 ± 0.70 kJ/mol	Harding 2008
1.3	2201.9	C (graphite) + CO2 (g) → 2 CO (g)	Δ_rG°(1165 K) = -33.545 ± 0.058 kJ/mol	Smith 1946, note COf, 3rd Law
1.3	3005.8	HCO (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 1132.53 ± 0.74 kJ/mol	Harding 2008
1.2	3015.11	HCO (g) → H (g) + CO (g)	Δ_rH°(0 K) = 60.2 ± 0.8 kJ/mol	Marenich 2003
1.2	3005.6	HCO (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 1132.11 ± 0.75 (×1.044) kJ/mol	Tajti 2004, est unc
1.1	2931.10	CH2O (g) → C (g) + 2 H (g) + O (g)	Δ_rH°(0 K) = 1495.36 ± 0.80 kJ/mol	Feller 2018a
1.1	2939.4	2 CH2O (g) → CH4 (g) + CO2 (g)	Δ_rH°(0 K) = -59.37 ± 0.40 kcal/mol	Boese 2004
1.1	2939.5	2 CH2O (g) → CH4 (g) + CO2 (g)	Δ_rH°(0 K) = -59.52 ± 0.40 kcal/mol	Karton 2006
1.0	3005.10	HCO (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 1132.87 ± 0.84 kJ/mol	Harding 2008
1.0	3005.12	HCO (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 1132.50 ± 0.84 kJ/mol	Harding 2008

Top 10 species with enthalpies of formation correlated to the Δ_fH° 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	Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units	Relative Molecular Mass	ATcT ID
99.8	Oxomethylium	[HCO]+ (g)	827.766	827.181	± 0.095	kJ/mol	29.01749 ± 0.00086	17030-74-9*0
99.6	Formaldehyde	CH2O (g, triplet)	196.010	192.708	± 0.095	kJ/mol	30.02598 ± 0.00087	50-00-0*1
99.6	Formaldehyde	CH2O (g, ortho singlet)	-105.254	-109.220	± 0.095	kJ/mol	30.02598 ± 0.00087	50-00-0*22
99.6	Formaldehyde	CH2O (g, para singlet)	-105.380	-109.221	± 0.095	kJ/mol	30.02598 ± 0.00087	50-00-0*21
99.6	Formaldehyde	CH2O (g, singlet)	-105.380	-109.221	± 0.095	kJ/mol	30.02598 ± 0.00087	50-00-0*2
99.6	Formaldehyde	CH2O (g)	-105.380	-109.221	± 0.095	kJ/mol	30.02598 ± 0.00087	50-00-0*0
98.3	Formaldehyde cation	[CH2O]+ (g)	944.861	941.240	± 0.096	kJ/mol	30.02543 ± 0.00087	54288-05-0*0
43.4	Formaldehyde	CH2O (aq, unhydrol)		-165.65	± 0.22	kJ/mol	30.02598 ± 0.00087	50-00-0*1000
22.9	Hydroxymethylene	HCOH (g, trans)	112.71	108.94	± 0.27	kJ/mol	30.02598 ± 0.00087	19710-56-6*1
22.9	Hydroxymethylene	HCOH (g)	112.71	108.95	± 0.27	kJ/mol	30.02598 ± 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
0.999	3006.1	HCO (g) → [HCO]+ (g)	Δ_rH°(0 K) = 65735.9 ± 0.5 cm-1	Mayer 1995, Foltynowicz 2001
0.776	3007.1	[HCO]- (g) → HCO (g)	Δ_rH°(0 K) = 0.313 ± 0.005 eV	Murray 1986
0.716	3034.10	HCO (g) → COH (g)	Δ_rH°(0 K) = 175.9 ± 0.8 kJ/mol	Marenich 2003
0.551	3017.2	CH2O (g) → HCO (g) + H (g)	Δ_rH°(0 K) = 30327.6 ± 0.9 cm-1	Terentis 1998
0.446	3017.1	CH2O (g) → HCO (g) + H (g)	Δ_rH°(0 K) = 30328.5 ± 1.0 cm-1	Terentis 1996, est unc
0.194	5153.9	OCHCHO (g, trans) → 2 HCO (g)	Δ_rH°(0 K) = 69.62 ± 0.30 kcal/mol	Karton 2011
0.191	4737.4	HCO (g) + 2 OH (g) → HCOO (g, cis) + H2O (g)	Δ_rH°(0 K) = -1.93 ± 1.60 kcal/mol	Ruscic G4
0.168	7528.6	HCCCO (g) + CH2O (g) → CH2CCO (g) + HCO (g)	Δ_rH°(0 K) = -11.70 ± 2.0 kJ/mol	Klippenstein 2017
0.166	7446.6	CH2CCHO (g) → CCH2 (g) + HCO (g)	Δ_rH°(0 K) = 274.15 ± 2.0 kJ/mol	Klippenstein 2017
0.166	4737.3	HCO (g) + 2 OH (g) → HCOO (g, cis) + H2O (g)	Δ_rH°(0 K) = -2.69 ± 1.72 kcal/mol	Ruscic G3X
0.156	8865.3	C6H5C(O)C6H5 (g) + HCO (g) → C6H5CO (g) + C6H5C(O)H (g)	Δ_rH°(0 K) = 0.28 ± 0.90 kcal/mol	Ruscic CBS-n
0.142	5167.6	OCHCO (g) + CH2O (g) → OCHCHO (g, trans) + HCO (g)	Δ_rH°(0 K) = 1.79 ± 2.00 kJ/mol	Klippenstein 2017
0.141	4736.6	HCO (g) + 2 OH (g) → HCOO (g, trans) + H2O (g)	Δ_rH°(0 K) = 2.02 ± 1.50 kcal/mol	Ruscic W1RO
0.126	8865.2	C6H5C(O)C6H5 (g) + HCO (g) → C6H5CO (g) + C6H5C(O)H (g)	Δ_rH°(0 K) = -0.76 ± 1.00 kcal/mol	Ruscic CBS-n
0.123	4736.4	HCO (g) + 2 OH (g) → HCOO (g, trans) + H2O (g)	Δ_rH°(0 K) = 3.23 ± 1.60 kcal/mol	Ruscic G4
0.107	4736.3	HCO (g) + 2 OH (g) → HCOO (g, trans) + H2O (g)	Δ_rH°(0 K) = 2.96 ± 1.72 kcal/mol	Ruscic G3X
0.096	5180.5	(C(O)OH)2 (g) + 2 HCO (g) → OCHCHO (g, trans) + 2 HOCO (g, trans)	Δ_rH°(0 K) = 16.73 ± 0.85 kcal/mol	Ruscic W1RO
0.086	5180.1	(C(O)OH)2 (g) + 2 HCO (g) → OCHCHO (g, trans) + 2 HOCO (g, trans)	Δ_rH°(0 K) = 17.04 ± 0.90 kcal/mol	Ruscic G3X
0.086	5180.4	(C(O)OH)2 (g) + 2 HCO (g) → OCHCHO (g, trans) + 2 HOCO (g, trans)	Δ_rH°(0 K) = 16.23 ± 0.90 kcal/mol	Ruscic CBS-n
0.079	5180.2	(C(O)OH)2 (g) + 2 HCO (g) → OCHCHO (g, trans) + 2 HOCO (g, trans)	Δ_rH°(0 K) = 15.36 ± 0.90 (×1.044) kcal/mol	Ruscic G4

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. 1.148 of the Thermochemical Network (2023); available at ATcT.anl.gov
4		T. L. Nguyen, J. Peeters, J.-F. Müller, A. Perera, D. H. Bross, B. Ruscic, and J. F. Stanton, Methanediol from Cloud-Processed Formaldehyde is Only a Minor Source of Atmospheric Formic Acid Natl. Acad. Sci. 120, e2304650120/1-8 (2023) [DOI: 10.1073/pnas.2304650120]
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.