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].

Methylperoxy

Formula: CH3OO (g)

CAS RN: 2143-58-0

ATcT ID: 2143-58-0*0

SMILES: CO[O]

InChI: InChI=1S/CH3O2/c1-3-2/h1H3

InChIKey: WTFNSXYULBQCQV-UHFFFAOYSA-N

Hills Formula: C1H3O2

2D Image:

Aliases: CH3OO; Methylperoxy; Methyldioxidanyl; Methyldioxy; Methylperoxyl; Methylperoxo; Methyl peroxide radical; Methyl peroxy radical; Methyldioxy radical

Relative Molecular Mass: 47.0333 ± 0.0010

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
22.52	13.07	± 0.34	kJ/mol

3D Image of CH3OO (g)

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Top contributors to the provenance of Δ_fH° of CH3OO (g)

The 20 contributors listed below account only for 65.9% of the provenance of Δ_fH° of CH3OO (g).
A total of 123 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
21.3	4630.6	CH3OO (g) → CH3 (g) + O2 (g)	Δ_rH°(0 K) = 30.40 ± 0.17 kcal/mol	Nguyen 2014a
10.8	4617.9	CH3OO (g) → C (g) + 3 H (g) + 2 O (g)	Δ_rH°(0 K) = 1830.74 ± 1. kJ/mol	Welch 2019, Welch 2018
6.7	4621.9	[CH3OO]- (g) → C (g) + 3 H (g) + 2 O (g)	Δ_rH°(0 K) = 1942.76 ± 1. kJ/mol	Welch 2019, Welch 2018
3.3	4620.9	[CH3OO]+ (g) → C (g) + 3 H (g) + 2 O (g)	Δ_rH°(0 K) = 840.85 ± 1. kJ/mol	Welch 2019, Welch 2018
2.9	4628.1	CH3OO (g) → [CH3]+ (g) + O2 (g)	Δ_rH°(0 K) = 11.15 ± 0.02 eV	Tang 2020a
2.6	4622.1	CH4 (g) + 2 H2O (g) → CH3OO (g) + 5/2 H2 (g)	Δ_rH°(0 K) = 567.06 ± 2.0 kJ/mol	Klippenstein 2017
2.4	4630.7	CH3OO (g) → CH3 (g) + O2 (g)	Δ_rH°(0 K) = 30.75 ± 0.50 kcal/mol	Nguyen 2014a, est unc
2.3	4618.13	CH3OO (g) → [CH3OO]+ (g)	Δ_rH°(0 K) = 10.259 ± 0.010 eV	Welch 2019, Welch 2018
2.1	4619.1	[CH3OO]- (g) → CH3OO (g)	Δ_rH°(0 K) = 1.161 ± 0.005 eV	Blanksby 2001
2.1	4528.9	CH3OOH (g) → C (g) + 4 H (g) + 2 O (g)	Δ_rH°(0 K) = 2184.34 ± 1. kJ/mol	Welch 2019, Welch 2018
1.2	4628.2	CH3OO (g) → [CH3]+ (g) + O2 (g)	Δ_rH°(0 K) = 11.164 ± 0.030 eV	Voronova 2018, Tang 2020a, est unc
1.1	3183.6	HC(O)OO (g, syn) + CH4 (g) → CH3OO (g) + CH2O (g)	Δ_rH°(0 K) = 83.83 ± 2.0 kJ/mol	Klippenstein 2017
1.0	4675.6	CH3CH2OO (g, gauche) + CH3 (g) → CH3OO (g) + CH3CH2 (g)	Δ_rH°(0 K) = 10.09 ± 2.00 kJ/mol	Klippenstein 2017
0.8	4626.6	CH3OO (g) + HOO (g) → CH3OOH (g) + O2 (g, triplet)	Δ_rH°(0 K) = -152.74 ± 2.0 kJ/mol	Klippenstein 2017
0.8	4623.10	CH3OOH (g) → CH3OO (g) + H (g)	Δ_rH°(0 K) = 353.47 ± 2.0 kJ/mol	Klippenstein 2017
0.8	4623.9	CH3OOH (g) → CH3OO (g) + H (g)	Δ_rH°(0 K) = 353.60 ± 2. kJ/mol	Welch 2019, Welch 2018
0.8	4624.9	CH3OO (g) + HOOH (g) → CH3OOH (g) + HOO (g)	Δ_rH°(0 K) = 6.76 ± 2.0 kJ/mol	Klippenstein 2017
0.8	4626.1	CH3OO (g) + HOO (g) → CH3OOH (g) + O2 (g, triplet)	Δ_rH°(0 K) = -36.14 ± 0.5 kcal/mol	Nguyen 2022
0.6	4631.8	CH3OO (g) + NO (g) → CH3O (g) + ONO (g)	Δ_rH°(0 K) = -11.77 ± 0.9 kcal/mol	Ruscic W1RO
0.5	4629.6	CH3OO (g) → CH3 (g) + O2 (g)	Δ_rG°(752.6 K) = 38.10 ± 1.90 (×2.278) kJ/mol	Knyazev 1998, Knyazev 1998, 3rd Law

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH3OO (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
58.5	Methylperoxy anion	[CH3OO]- (g)	-89.69	-99.83	± 0.45	kJ/mol	47.0339 ± 0.0010	35683-44-4*0
35.2	Methyl hydroperoxide	CH3OOH (g)	-114.82	-127.64	± 0.42	kJ/mol	48.0413 ± 0.0010	3031-73-0*0
27.7	Methoxyoxoniumylidene	[CH3OO]+ (g)	1012.31	1003.48	± 0.67	kJ/mol	47.0328 ± 0.0010	86475-50-5*0
23.9	Hydroxymethyleneoxonium	[CH2OOH]+ (g)	792.97	782.84	± 0.63	kJ/mol	47.0328 ± 0.0010	77144-12-8*0
20.4	Ethylperoxy	CH3CH2OO (g)	-6.13	-22.10	± 0.62	kJ/mol	61.0599 ± 0.0017	3170-61-4*0
20.4	Ethylperoxy	CH3CH2OO (g, gauche)	-6.13	-22.16	± 0.62	kJ/mol	61.0599 ± 0.0017	3170-61-4*3
17.8	Ethaneperoxolate	[CH3CH2OO]- (g, gauche)	-120.36	-136.98	± 0.70	kJ/mol	61.0604 ± 0.0017	268728-75-2*3
17.8	Ethaneperoxolate	[CH3CH2OO]- (g)	-120.36	-136.42	± 0.70	kJ/mol	61.0604 ± 0.0017	268728-75-2*0
17.5	Hydroperoxymethyl	CH2OOH (g)	73.26	65.96	± 0.97	kJ/mol	47.0333 ± 0.0010	74087-87-9*0
16.7	Peroxyformyl	HC(O)OO (g, syn)	-100.42	-105.73	± 0.67	kJ/mol	61.0168 ± 0.0012	56240-83-6*1

Most Influential reactions involving CH3OO (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
0.589	4619.1	[CH3OO]- (g) → CH3OO (g)	Δ_rH°(0 K) = 1.161 ± 0.005 eV	Blanksby 2001
0.465	4618.13	CH3OO (g) → [CH3OO]+ (g)	Δ_rH°(0 K) = 10.259 ± 0.010 eV	Welch 2019, Welch 2018
0.217	4630.6	CH3OO (g) → CH3 (g) + O2 (g)	Δ_rH°(0 K) = 30.40 ± 0.17 kcal/mol	Nguyen 2014a
0.176	8440.5	C6H5OOH (g) + CH3OO (g) → C6H5OO (g) + CH3OOH (g)	Δ_rH°(0 K) = 0.83 ± 0.85 kcal/mol	Ruscic W1RO
0.157	8440.2	C6H5OOH (g) + CH3OO (g) → C6H5OO (g) + CH3OOH (g)	Δ_rH°(0 K) = -0.09 ± 0.90 kcal/mol	Ruscic G4
0.157	8440.4	C6H5OOH (g) + CH3OO (g) → C6H5OO (g) + CH3OOH (g)	Δ_rH°(0 K) = 0.51 ± 0.90 kcal/mol	Ruscic CBS-n
0.157	8440.1	C6H5OOH (g) + CH3OO (g) → C6H5OO (g) + CH3OOH (g)	Δ_rH°(0 K) = 1.15 ± 0.90 kcal/mol	Ruscic G3X
0.147	4619.10	[CH3OO]- (g) → CH3OO (g)	Δ_rH°(0 K) = 1.161 ± 0.010 eV	Welch 2019, Welch 2018
0.146	4670.6	CH3CH2OO (g, gauche) + CH3OOH (g) → CH3CH2OOH (g) + CH3OO (g)	Δ_rH°(0 K) = 0.81 ± 1.50 kJ/mol	Welch 2019, Welch 2018
0.127	8440.3	C6H5OOH (g) + CH3OO (g) → C6H5OO (g) + CH3OOH (g)	Δ_rH°(0 K) = 1.17 ± 1.0 kcal/mol	Ruscic CBS-n
0.120	3183.6	HC(O)OO (g, syn) + CH4 (g) → CH3OO (g) + CH2O (g)	Δ_rH°(0 K) = 83.83 ± 2.0 kJ/mol	Klippenstein 2017
0.114	4697.5	CH3CHOOH (g) + CH3OO (g) → CH3CH2OO (g, gauche) + CH2OOH (g)	Δ_rH°(0 K) = 1.10 ± 0.85 kcal/mol	Ruscic W1RO
0.110	4617.9	CH3OO (g) → C (g) + 3 H (g) + 2 O (g)	Δ_rH°(0 K) = 1830.74 ± 1. kJ/mol	Welch 2019, Welch 2018
0.106	8437.2	C6H5OO (g) + CH3 (g) → C6H5 (g) + CH3OO (g)	Δ_rH°(0 K) = 16.66 ± 1.0 kcal/mol	Ruscic G4
0.102	4697.1	CH3CHOOH (g) + CH3OO (g) → CH3CH2OO (g, gauche) + CH2OOH (g)	Δ_rH°(0 K) = 1.14 ± 0.90 kcal/mol	Ruscic G3X
0.102	4697.4	CH3CHOOH (g) + CH3OO (g) → CH3CH2OO (g, gauche) + CH2OOH (g)	Δ_rH°(0 K) = 1.34 ± 0.90 kcal/mol	Ruscic CBS-n
0.102	4697.2	CH3CHOOH (g) + CH3OO (g) → CH3CH2OO (g, gauche) + CH2OOH (g)	Δ_rH°(0 K) = 1.28 ± 0.90 kcal/mol	Ruscic G4
0.101	4675.6	CH3CH2OO (g, gauche) + CH3 (g) → CH3OO (g) + CH3CH2 (g)	Δ_rH°(0 K) = 10.09 ± 2.00 kJ/mol	Klippenstein 2017
0.098	8435.5	C6H5OO (g) + CH3O (g) → C6H5O (g) + CH3OO (g)	Δ_rH°(0 K) = -21.48 ± 0.9 kcal/mol	Ruscic W1RO
0.088	8437.1	C6H5OO (g) + CH3 (g) → C6H5 (g) + CH3OO (g)	Δ_rH°(0 K) = 17.83 ± 1.1 kcal/mol	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. 1.176 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.