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]

Hydroxymethylium

Formula: [CH2OH]+ (g)

CAS RN: 18682-95-6

ATcT ID: 18682-95-6*0

SMILES: [CH2+]O

InChI: InChI=1S/CH3O/c1-2/h2H,1H2/q+1

InChIKey: NRCYHMDIJIIHBJ-UHFFFAOYSA-N

InChI: InChI=1S/CH2O/c1-2/h1H2/p+1

InChIKey: WSFSSNUMVMOOMR-UHFFFAOYSA-O

Hills Formula: C1H3O1+

2D Image:

Aliases: [CH2OH]+; Hydroxymethylium; Methylideneoxidanium; Hydroxymethyl cation; Hydroxymethyl ion (1+); Protonated formaldehyde; Formaldehyde, conjugate acid; CH2OH+; [H2COH]+; H2COH+; [OHCH2]+; OHCH2+; [HOCH2]+; HOCH2+

Relative Molecular Mass: 31.03337 ± 0.00088

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
717.67	709.73	± 0.19	kJ/mol

3D Image of [CH2OH]+ (g)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of [CH2OH]+ (g)

The 20 contributors listed below account only for 71.5% of the provenance of Δ_fH° of [CH2OH]+ (g).
A total of 195 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
20.9	2871.1	CH3OH (g) → [CH2OH]+ (g) + H (g)	Δ_rH°(0 K) = 11.6454 ± 0.0017 eV	Borkar 2011
17.2	2873.1	[CH2OH]+ (g) → CH2O (g) + H+ (g)	Δ_rH°(0 K) = 704.98 ± 0.39 kJ/mol	Czako 2009
7.5	2823.2	CH3OH (g) + 3/2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -182.72 ± 0.05 (×1.719) kcal/mol	Rossini 1932a, Domalski 1972, Weltner 1951, Rossini 1934a, note old units, mw conversion
6.7	2871.2	CH3OH (g) → [CH2OH]+ (g) + H (g)	Δ_rH°(0 K) = 11.649 ± 0.003 eV	Ruscic 1993
2.0	2825.1	CH3OH (g) → CH4 (g) + O (g, singlet)	Δ_rH°(0 K) = 133.94 ± 0.17 kcal/mol	Nguyen 2015a
1.8	2824.1	CH3OH (g) → CH3 (g) + OH (g)	Δ_rH°(0 K) = 90.12 ± 0.17 kcal/mol	Nguyen 2015a
1.7	2827.1	CH3OH (g) → CH2 (g, triplet) + H2O (g)	Δ_rH°(0 K) = 81.77 ± 0.17 kcal/mol	Nguyen 2015a
1.7	2826.1	CH3OH (g) → CH2 (g, singlet) + H2O (g)	Δ_rH°(0 K) = 90.84 ± 0.17 kcal/mol	Nguyen 2015a
1.6	2865.3	CH2OH (g) → [CH2OH]+ (g)	Δ_rH°(0 K) = 7.553 ± 0.006 (×1.242) eV	Ruscic 1991, Ruscic 1991a, Litorja 1998a
1.5	2831.1	CH3OH (cr,l) + 3/2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(303.15 K) = -725.36 ± 0.13 (×6.037) kJ/mol	Chao 1965, mw conversion
1.4	2897.1	CH3OH (g) → CH2O (g) + H2 (g)	Δ_rH°(0 K) = 20.28 ± 0.17 kcal/mol	Nguyen 2015a
1.2	2943.6	CH3OH (g) → HCOH (g, trans) + H2 (g)	Δ_rH°(0 K) = 72.44 ± 0.17 kcal/mol	Nguyen 2015a
0.8	2965.11	[HCO]+ (g) → H+ (g) + CO (g)	Δ_rH°(0 K) = 586.51 ± 0.2 kJ/mol	Czako 2008
0.7	3854.1	CH3OH (g) + [CH3CHOH]+ (g) → CH3CH2OH (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 0.848 ± 0.006 eV	Ruscic 1993, Ruscic 1994c
0.7	120.2	1/2 O2 (g) + H2 (g) → H2O (cr,l)	Δ_rH°(298.15 K) = -285.8261 ± 0.040 kJ/mol	Rossini 1939, Rossini 1931, Rossini 1931b, note H2Oa, Rossini 1930
0.7	2245.1	2 H2 (g) + C (graphite) → CH4 (g)	Δ_rG°(1165 K) = 37.521 ± 0.068 kJ/mol	Smith 1946, note COf, 3rd Law
0.7	2867.9	[CH2OH]+ (g) → C (g) + 3 H (g) + O (g)	Δ_rH°(0 K) = 212.63 ± 0.50 kcal/mol	Matus 2007
0.7	2536.8	CH3NH2 (g) + H2O (g) → CH3OH (g) + NH3 (g)	Δ_rH°(0 K) = 4.07 ± 0.25 kcal/mol	Karton 2011
0.6	2872.1	CH2OH (g) → CH2O (g) + H (g)	Δ_rH°(0 K) = 10160 ± 70 cm-1	Ryazanov 2012
0.6	2816.11	CH3OH (g) → 4 H (g) + C (g) + O (g)	Δ_rH°(0 K) = 480.94 ± 0.30 kcal/mol	Karton 2011

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [CH2OH]+ (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
71.5	Methanol	CH3OH (g)	-190.04	-200.92	± 0.15	kJ/mol	32.04186 ± 0.00090	67-56-1*0
70.1	Methanol	CH3OH (cr,l)	-235.28	-238.62	± 0.16	kJ/mol	32.04186 ± 0.00090	67-56-1*500
32.7	Hydroxymethyl	CH2OH (g)	-10.37	-16.67	± 0.28	kJ/mol	31.03392 ± 0.00088	2597-43-5*0
32.5	Methanol cation	[CH3OH]+ (g)	856.81	846.49	± 0.32	kJ/mol	32.04131 ± 0.00090	12538-91-9*0
29.1	Methoxy	CH3O (g)	28.92	21.55	± 0.27	kJ/mol	31.03392 ± 0.00088	2143-68-2*0
29.0	Methoxide	[CH3O]- (g)	-122.47	-130.20	± 0.27	kJ/mol	31.03447 ± 0.00088	3315-60-4*0
21.2	Methyl nitrite	CH3ONO (g)	-55.54	-66.21	± 0.45	kJ/mol	61.0401 ± 0.0010	624-91-9*0
21.2	Methyl nitrite	CH3ONO (g, cis)	-55.54	-67.32	± 0.45	kJ/mol	61.0401 ± 0.0010	624-91-9*2
20.4	Formaldehyde	CH2O (g)	-105.389	-109.229	± 0.096	kJ/mol	30.02598 ± 0.00087	50-00-0*0
20.4	Formaldehyde	CH2O (g, singlet)	-105.389	-109.229	± 0.096	kJ/mol	30.02598 ± 0.00087	50-00-0*2

Most Influential reactions involving [CH2OH]+ (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
0.612	2871.1	CH3OH (g) → [CH2OH]+ (g) + H (g)	Δ_rH°(0 K) = 11.6454 ± 0.0017 eV	Borkar 2011
0.405	2630.1	HCN (g) + [CH2OH]+ (g) → [HCNH]+ (g) + CH2O (g)	Δ_rG°(300 K) = 0.5 ± 0.5 kcal/mol	Wolf 1977, est unc
0.334	3854.1	CH3OH (g) + [CH3CHOH]+ (g) → CH3CH2OH (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 0.848 ± 0.006 eV	Ruscic 1993, Ruscic 1994c
0.230	2873.1	[CH2OH]+ (g) → CH2O (g) + H+ (g)	Δ_rH°(0 K) = 704.98 ± 0.39 kJ/mol	Czako 2009
0.196	2871.2	CH3OH (g) → [CH2OH]+ (g) + H (g)	Δ_rH°(0 K) = 11.649 ± 0.003 eV	Ruscic 1993
0.145	2865.3	CH2OH (g) → [CH2OH]+ (g)	Δ_rH°(0 K) = 7.553 ± 0.006 (×1.242) eV	Ruscic 1991, Ruscic 1991a, Litorja 1998a
0.105	6567.5	[CH3C(OH)CH3]+ (g) + CH2O (g) → CH3C(O)CH3 (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 24.50 ± 0.8 kcal/mol	Ruscic W1RO
0.074	2881.9	[CH2OH]+ (g) → [CH3O]+ (g)	Δ_rH°(0 K) = 82.70 ± 0.50 kcal/mol	Matus 2007
0.067	6567.4	[CH3C(OH)CH3]+ (g) + CH2O (g) → CH3C(O)CH3 (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 24.32 ± 1.0 kcal/mol	Ruscic CBS-n
0.067	6567.2	[CH3C(OH)CH3]+ (g) + CH2O (g) → CH3C(O)CH3 (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 24.40 ± 1.0 kcal/mol	Ruscic G4
0.046	6567.1	[CH3C(OH)CH3]+ (g) + CH2O (g) → CH3C(O)CH3 (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 24.50 ± 1.2 kcal/mol	Ruscic G3X
0.039	6567.3	[CH3C(OH)CH3]+ (g) + CH2O (g) → CH3C(O)CH3 (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 24.38 ± 1.3 kcal/mol	Ruscic CBS-n
0.038	2865.1	CH2OH (g) → [CH2OH]+ (g)	Δ_rH°(0 K) = 7.56 ± 0.01 (×1.445) eV	Dyke 1984, Baker 1995a
0.020	2865.2	CH2OH (g) → [CH2OH]+ (g)	Δ_rH°(0 K) = 7.56 ± 0.02 eV	Tao 1992
0.019	3855.9	CH3OH (g) + [CH3CHOH]+ (g, anti) → CH3CH2OH (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 0.827 ± 0.025 eV	Matus 2007, est unc
0.018	4855.7	(CH2OH)2 (g) → CH2OH (g) + [CH2OH]+ (g)	Δ_rH°(0 K) = 11.178 ± 0.040 eV	Ruscic W1RO
0.013	2881.7	[CH2OH]+ (g) → [CH3O]+ (g)	Δ_rH°(0 K) = 82.92 ± 1.2 kcal/mol	Ruscic CBS-n
0.013	2881.8	[CH2OH]+ (g) → [CH3O]+ (g)	Δ_rH°(0 K) = 82.56 ± 1.2 kcal/mol	Ruscic W1RO
0.012	2865.12	CH2OH (g) → [CH2OH]+ (g)	Δ_rH°(0 K) = 7.523 ± 0.025 eV	Matus 2007, est unc
0.011	2881.4	[CH2OH]+ (g) → [CH3O]+ (g)	Δ_rH°(0 K) = 81.80 ± 1.3 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. 1.124 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.