Selected ATcT [1, 2] enthalpy of formation based on version 1.156 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.148 to include species relevant to a recent study of the oxidation of ethylene [4] as well as new measurements that led to refining the thermochemistry of CF and SiF and their cations [5].

Methylium

Formula: [CH3]+ (g)
CAS RN: 14531-53-4
ATcT ID: 14531-53-4*0
SMILES: [CH3+]
InChI: InChI=1S/CH3/h1H3/q+1
InChIKey: JUHDUIDUEUEQND-UHFFFAOYSA-N
Hills Formula: C1H3+

2D Image:

[CH3+]
Aliases: [CH3]+; Methylium; Methylcarbonium; Methyl carbonium; Methyl cation; Methyl ion (1+)
Relative Molecular Mass: 15.03397 ± 0.00083

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
1099.3541095.411± 0.045kJ/mol

3D Image of [CH3]+ (g)

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Top contributors to the provenance of ΔfH° of [CH3]+ (g)

The 20 contributors listed below account only for 65.0% of the provenance of ΔfH° of [CH3]+ (g).
A total of 317 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
37.72359.1 H2 (g) C (graphite) → CH4 (g) ΔrG°(1165 K) = 37.521 ± 0.068 kJ/molSmith 1946, note COf, 3rd Law
6.72357.7 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.578 ± 0.078 kJ/molSchley 2010
6.12381.1 CH4 (g) → [CH3]+ (g) H (g) ΔrH°(0 K) = 14.32271 ± 0.00013 eVChang 2017
5.7125.2 1/2 O2 (g) H2 (g) → H2O (cr,l) ΔrH°(298.15 K) = -285.8261 ± 0.040 kJ/molRossini 1939, Rossini 1931, Rossini 1931b, note H2Oa, Rossini 1930
1.02214.7 C (graphite) O2 (g) → CO2 (g) ΔrH°(298.15 K) = -393.464 ± 0.024 kJ/molHawtin 1966, note CO2e
0.92357.4 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.61 ± 0.21 kJ/molDale 2002
0.82252.11 CO (g) → C (g) O (g) ΔrH°(0 K) = 1071.92 ± 0.10 (×1.242) kJ/molThorpe 2021
0.62262.2 CO (g) → C+ (g) O (g) ΔrH°(0 K) = 22.3713 ± 0.0015 eVNg 2007
0.62357.6 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.44 ± 0.26 kJ/molGOMB Ref Calorimeter, Alexandrov 2002
0.62357.8 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.482 ± 0.260 kJ/molHaloua 2015
0.42270.9 C (graphite) CO2 (g) → 2 CO (g) ΔrG°(1165 K) = -33.545 ± 0.058 kJ/molSmith 1946, note COf, 3rd Law
0.42371.12 CH3 (g) → C (g) + 3 H (g) ΔrH°(0 K) = 289.11 ± 0.10 kcal/molFeller 2016, note unc2
0.42214.4 C (graphite) O2 (g) → CO2 (g) ΔrH°(298.15 K) = -393.462 ± 0.038 kJ/molLewis 1965, note CO2d
0.42214.5 C (graphite) O2 (g) → CO2 (g) ΔrH°(298.15 K) = -393.468 ± 0.038 kJ/molFraser 1952, note CO2f
0.4115.11 H2O (g) → O (g) + 2 H (g) ΔrH°(0 K) = 917.80 ± 0.15 kJ/molThorpe 2021
0.32413.1 CH3 (g) → CH2 (g, triplet) H (g) ΔrH°(0 K) = 109.26 ± 0.08 kcal/molFeller 2016, est unc, note unc2
0.3157.1 OH (g) → [OH]+ (g) ΔrH°(0 K) = 104989 ± 5 (×2.327) cm-1Wiedmann 1992, note unc
0.38842.1 CH4 (g) → HCCCCCH3 (g) + 8 H2 (g) ΔrH°(0 K) = 750.67 ± 2.00 kJ/molKlippenstein 2017
0.32357.5 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.43 ± 0.35 kJ/molAlexandrov 2002a, Alexandrov 2002
0.32357.1 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(303.15 K) = -889.849 ± 0.350 kJ/molRossini 1931a, Rossini 1931b, Prosen 1945, Rossini 1940, note CH4

Top 10 species with enthalpies of formation correlated to the ΔfH° of [CH3]+ (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 Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass
ATcT ID
96.1 MethaneCH4 (g)C-66.541-74.511± 0.044kJ/mol16.04246 ±
0.00085
74-82-8*0
88.5 MethylCH3 (g)[CH3]149.882146.481± 0.050kJ/mol15.03452 ±
0.00083
2229-07-4*0
74.3 Methane cation[CH4]+ (g)[CH4+]1150.6881144.305± 0.057kJ/mol16.04191 ±
0.00085
20741-88-2*0
44.1 Carbonic acidC(O)(OH)2 (aq, undissoc)OC(=O)O-698.670± 0.028kJ/mol62.0248 ±
0.0012
463-79-6*1000
43.7 WaterH2O (cr, l, eq.press.)O-286.276-285.804± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*499
43.7 WaterH2O (l, eq.press.)O-285.804± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*589
43.7 WaterH2O (l)O-285.802± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*590
43.7 Oxonium[H3O]+ (aq)[OH3+]-285.802± 0.022kJ/mol19.02267 ±
0.00037
13968-08-6*800
43.7 WaterH2O (cr,l)O-286.274-285.802± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*500
43.7 WaterH2O (g)O-238.904-241.807± 0.022kJ/mol18.01528 ±
0.00033
7732-18-5*0

Most Influential reactions involving [CH3]+ (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
0.9572381.1 CH4 (g) → [CH3]+ (g) H (g) ΔrH°(0 K) = 14.32271 ± 0.00013 eVChang 2017
0.5226222.2 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.251 ± 0.0024 eVLee 2007
0.4112374.2 CH3 (g) → [CH3]+ (g) ΔrH°(0 K) = 79369.9 ± 3 cm-1Schulenburg 2006, note CH3
0.4112374.1 CH3 (g) → [CH3]+ (g) ΔrH°(0 K) = 79370.4 ± 3 cm-1Schulenburg 2006, note CH3
0.1986222.1 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.248 ± 0.003 (×1.297) eVBodi 2009, Bodi 2023
0.1506200.1 CH3Br (g) → [CH3]+ (g) Br (g) ΔrH°(0 K) = 12.834 ± 0.002 (×2.538) eVSong 2001
0.0792374.4 CH3 (g) → [CH3]+ (g) ΔrH°(0 K) = 79363 ± 3 (×2.278) cm-1Blush 1993, note CH3
0.0396222.3 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.243 ± 0.008 (×1.091) eVLee 2007, Bodi 2009
0.0362375.12 CH3 (g) → [CH3]+ (g) ΔrH°(0 K) = 226.946 ± 0.029 kcal/molFeller 2017a
0.0294576.1 CH3OO (g) → [CH3]+ (g) O2 (g) ΔrH°(0 K) = 11.15 ± 0.02 eVTang 2020a
0.0226222.5 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.24 ± 0.01 (×1.164) eVMintz 1976
0.0202544.5 [CH2CH]+ (g) CH4 (g) → [CH3]+ (g) CH2CH2 (g) ΔrH°(0 K) = 25.65 ± 0.9 kcal/molRuscic W1RO, Lago 2006
0.0162544.4 [CH2CH]+ (g) CH4 (g) → [CH3]+ (g) CH2CH2 (g) ΔrH°(0 K) = 26.09 ± 1.0 kcal/molRuscic CBS-n
0.0162544.2 [CH2CH]+ (g) CH4 (g) → [CH3]+ (g) CH2CH2 (g) ΔrH°(0 K) = 25.09 ± 1.0 kcal/molRuscic G4
0.0162381.3 CH4 (g) → [CH3]+ (g) H (g) ΔrH°(0 K) = 14.323 ± 0.001 eVWeitzel 1999, Weitzel 2001
0.0134576.2 CH3OO (g) → [CH3]+ (g) O2 (g) ΔrH°(0 K) = 11.164 ± 0.030 eVVoronova 2018, Tang 2020a, est unc
0.0102362.4 [CH5]+ (g) → [CH3]+ (g) H2 (g) ΔrH°(0 K) = 42.0 ± 1 kcal/molMuller 1997
0.0096200.3 CH3Br (g) → [CH3]+ (g) Br (g) ΔrH°(0 K) = 12.82 ± 0.02 eVTraeger 1981, AE corr, note unc2
0.0096222.4 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.269 ± 0.003 (×5.907) eVSong 2001
0.0082544.1 [CH2CH]+ (g) CH4 (g) → [CH3]+ (g) CH2CH2 (g) ΔrH°(0 K) = 24.36 ± 1.1 (×1.269) kcal/molRuscic 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 21st 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. 1.156 of the Thermochemical Network (2024); available at ATcT.anl.gov
4   N. A. Seifert, B. Ruscic, R. Sivaramakrishnan, and K. Prozument,
The C2H4O Isomers in the Oxidation of Ethylene
J. Mol. Spectrosc. 398, 111847/1-8 (2023) [DOI: 10.1016/j.jms.2023.111847]
5   U. Jacovella, B. Ruscic, N. L. Chen, H.-L. Le, S. Boyé-Péronne, S. Hartweg, M. Roy-Chowdhury, G. A. Garcia, J.-C. Loison, and B. Gans,
Refining Thermochemical Properties of CF, SiF, and Their Cations by Combining Photoelectron Spectroscopy, Quantum Chemical Calculations, and the Active Thermochemical Tables Approach
Phys. Chem. Chem. Phys. 25, 30838-30847 (2023) [DOI: 10.1039/D3CP04244H]
6   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]
7   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 [6] and Ruscic and Bross[7]).
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.