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]

Hydroxymethyliumylidene

Formula: [COH]+ (g)

CAS RN: 60528-75-8

ATcT ID: 60528-75-8*0

SMILES: [C+]O

InChI: InChI=1S/CHO/c1-2/h2H/q+1

InChIKey: FIRPXVMETWVPCB-UHFFFAOYSA-N

Hills Formula: C1H1O1+

2D Image:

Aliases: Hydroxymethyliumylidene; Hydroxymethyliumylidene ion; Hydroxymethyliumylidene cation; Hydroxymethyliumylidene ion (1+); Isoformylium; Isoformylium ion; Isoformylium cation; Isoformylium ion (1+); Isoformyl cation; Isoformyl ion (1+); Hydroxymethylidyne cation; Hydroxymethylidyne ion (1+); [COH]+; COH+; [HOC]+; HOC+; 97467-05-5

Relative Molecular Mass: 29.01749 ± 0.00086

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
986.01	987.65	± 0.83	kJ/mol

3D Image of [COH]+ (g)

spin ON spin OFF

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

The 18 contributors listed below account for 90.5% of the provenance of Δ_fH° of [COH]+ (g).

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
15.4	2989.4	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.81 ± 0.5 kcal/mol	Martin 1993
11.8	2989.5	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 13224 ± 200 cm-1	Mladenovic 1998, est unc
10.7	2989.3	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.78 ± 0.6 kcal/mol	Martin 1993
8.0	2994.4	[COH]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 102.36 ± 0.7 kcal/mol	Martin 1993, est unc
7.8	2989.8	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 38.12 ± 0.7 kcal/mol	Grunenberg 2003, Ruscic G3B3, est unc
6.0	2989.6	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.66 ± 0.8 kcal/mol	Yamaguchi 1994, est unc
5.3	2994.1	[COH]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 35953 ± 300 cm-1	Mladenovic 1998, est unc
4.0	2979.8	COH (g) → [COH]+ (g)	Δ_rH°(0 K) = 7.984 ± 0.040 eV	Ruscic W1RO
3.9	2994.3	[COH]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 102.68 ± 1 kcal/mol	Martin 1993, est unc
2.6	2988.8	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 38.23 ± 1.2 kcal/mol	Ruscic W1RO
2.2	2988.4	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.65 ± 1.3 kcal/mol	Ruscic G4
2.2	2988.7	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.60 ± 1.3 kcal/mol	Ruscic CBS-n
1.9	2988.3	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 38.75 ± 1.4 kcal/mol	Ruscic G3X
1.8	2989.7	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 160.6 ± 6 kJ/mol	Ma 1992, est unc
1.7	2982.8	[COH]+ (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 44.70 ± 1.50 kcal/mol	Ruscic W1RO
1.5	2982.4	[COH]+ (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 45.55 ± 1.60 kcal/mol	Ruscic G4
1.5	2982.7	[COH]+ (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 45.34 ± 1.60 kcal/mol	Ruscic CBS-n
1.5	2988.6	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.83 ± 1.6 kcal/mol	Ruscic CBS-n

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [COH]+ (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
8.6	Oxomethylium	[HCO]+ (g)	827.757	827.172	± 0.096	kJ/mol	29.01749 ± 0.00086	17030-74-9*0
8.6	Formyl	HCO (g)	41.381	41.755	± 0.096	kJ/mol	29.01804 ± 0.00086	2597-44-6*0
8.6	Formaldehyde	CH2O (g, triplet)	196.002	192.699	± 0.096	kJ/mol	30.02598 ± 0.00087	50-00-0*1
8.6	Formaldehyde	CH2O (g, ortho singlet)	-105.263	-109.229	± 0.096	kJ/mol	30.02598 ± 0.00087	50-00-0*22
8.6	Formaldehyde	CH2O (g, para singlet)	-105.389	-109.229	± 0.096	kJ/mol	30.02598 ± 0.00087	50-00-0*21
8.6	Formaldehyde	CH2O (g, singlet)	-105.389	-109.229	± 0.096	kJ/mol	30.02598 ± 0.00087	50-00-0*2
8.6	Formaldehyde	CH2O (g)	-105.389	-109.229	± 0.096	kJ/mol	30.02598 ± 0.00087	50-00-0*0
8.5	Formaldehyde cation	[CH2O]+ (g)	944.853	941.232	± 0.097	kJ/mol	30.02543 ± 0.00087	54288-05-0*0
8.2	Isoformyl	COH (g)	217.25	217.63	± 0.69	kJ/mol	29.01804 ± 0.00086	71080-92-7*0
2.2	Carbon	C (g)	711.404	716.889	± 0.044	kJ/mol	12.01070 ± 0.00080	7440-44-0*0

Most Influential reactions involving [COH]+ (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
0.156	2989.4	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.81 ± 0.5 kcal/mol	Martin 1993
0.119	2989.5	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 13224 ± 200 cm-1	Mladenovic 1998, est unc
0.108	2989.3	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.78 ± 0.6 kcal/mol	Martin 1993
0.080	2994.4	[COH]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 102.36 ± 0.7 kcal/mol	Martin 1993, est unc
0.079	2989.8	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 38.12 ± 0.7 kcal/mol	Grunenberg 2003, Ruscic G3B3, est unc
0.071	2979.8	COH (g) → [COH]+ (g)	Δ_rH°(0 K) = 7.984 ± 0.040 eV	Ruscic W1RO
0.061	2989.6	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.66 ± 0.8 kcal/mol	Yamaguchi 1994, est unc
0.053	2994.1	[COH]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 35953 ± 300 cm-1	Mladenovic 1998, est unc
0.039	2994.3	[COH]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 102.68 ± 1 kcal/mol	Martin 1993, est unc
0.027	2988.8	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 38.23 ± 1.2 kcal/mol	Ruscic W1RO
0.023	2988.4	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.65 ± 1.3 kcal/mol	Ruscic G4
0.023	2988.7	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.60 ± 1.3 kcal/mol	Ruscic CBS-n
0.021	2979.4	COH (g) → [COH]+ (g)	Δ_rH°(0 K) = 7.974 ± 0.073 eV	Ruscic G4
0.020	2979.7	COH (g) → [COH]+ (g)	Δ_rH°(0 K) = 7.932 ± 0.075 eV	Ruscic CBS-n
0.020	2988.3	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 38.75 ± 1.4 kcal/mol	Ruscic G3X
0.019	2989.7	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 160.6 ± 6 kJ/mol	Ma 1992, est unc
0.017	2982.8	[COH]+ (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 44.70 ± 1.50 kcal/mol	Ruscic W1RO
0.015	2982.7	[COH]+ (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 45.34 ± 1.60 kcal/mol	Ruscic CBS-n
0.015	2982.4	[COH]+ (g) → H (g) + O (g) + C (g)	Δ_rH°(0 K) = 45.55 ± 1.60 kcal/mol	Ruscic G4
0.015	2988.6	[HCO]+ (g) → [COH]+ (g)	Δ_rH°(0 K) = 37.83 ± 1.6 kcal/mol	Ruscic CBS-n

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.