Selected ATcT [1, 2] enthalpy of formation based on version 1.122g of the Thermochemical Network [3]

This version of ATcT results was generated from an expansion of version 1.122e [4] to include results centered on the determination of the appearance energy of CH3+ from CH4. [5].

Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Methyl iodide cation[CH3I]+ (g)C[I+]944.79935.40± 0.18kJ/mol141.93844 ±

Representative Geometry of [CH3I]+ (g)

spin ON           spin OFF

Top contributors to the provenance of ΔfH° of [CH3I]+ (g)

The 8 contributors listed below account for 90.0% of the provenance of ΔfH° of [CH3I]+ (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.

Reaction Measured Quantity Reference
44.44382.2 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.251 ± 0.0024 eVLee 2007
24.94382.1 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.248 ± 0.003 (×1.067) eVBodi 2009
5.81888.1 H2 (g) C (graphite) → CH4 (g) ΔrG°(1165 K) = 37.521 ± 0.068 kJ/molSmith 1946, note COf, 3rd Law
4.04382.3 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.243 ± 0.008 eVLee 2007, Bodi 2009
3.74384.4 CH3I (g) HI (g) → I2 (g) CH4 (g) ΔrG°(669 K) = -10.34 ± 0.09 (×2.134) kcal/molGoy 1965, 3rd Law
3.44384.2 CH3I (g) HI (g) → I2 (g) CH4 (g) ΔrG°(630.5 K) = -10.48 ± 0.08 (×2.484) kcal/molGolden 1965, 3rd Law, Cox 1970
2.24382.5 CH3I (g) → [CH3]+ (g) I (g) ΔrH°(0 K) = 12.24 ± 0.01 (×1.067) eVMintz 1976
1.34396.1 CH3I (l) + 7/2 O2 (g) → 2 CO2 (g) + 3 H2O (l) I2 (cr,l) ΔrH°(298.15 K) = -1617.2 ± 0.6 (×4.861) kJ/molCarson 1993

Top 10 species with enthalpies of formation correlated to the ΔfH° of [CH3I]+ (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.

Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
99.7 IodomethaneCH3I (g)CI24.5014.97± 0.18kJ/mol141.93899 ±
89.5 IodomethaneCH3I (l)CI-12.18± 0.20kJ/mol141.93899 ±
31.8 Methylium[CH3]+ (g)[CH3+]1099.3401095.396± 0.057kJ/mol15.03397 ±
30.4 MethaneCH4 (g)C-66.557-74.526± 0.055kJ/mol16.04246 ±
29.2 MethylCH3 (g)[CH3]149.872146.458± 0.060kJ/mol15.03452 ±
25.4 Methane cation[CH4]+ (g)[CH4+]1150.6731144.290± 0.066kJ/mol16.04191 ±
9.7 BromomethaneCH3Br (g)CBr-20.88-36.28± 0.18kJ/mol94.9385 ±
9.4 Methyl bromide cation[CH3Br]+ (g)C[Br+]996.24981.32± 0.18kJ/mol94.9380 ±
9.1 BromomethaneCH3Br (l)CBr-56.60-59.61± 0.19kJ/mol94.9385 ±
8.5 ChloromethaneCH3Cl (g)CCl-74.61-82.54± 0.19kJ/mol50.4872 ±

Most Influential reactions involving [CH3I]+ (g)

Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.

Reaction Measured Quantity Reference
0.9044381.3 CH3I (g) → [CH3I]+ (g) ΔrH°(0 K) = 76930.0 ± 1.0 cm-1Baig 1981
0.0564381.1 CH3I (g) → [CH3I]+ (g) ΔrH°(0 K) = 76932 ± 4 cm-1Urban 2002
0.0364381.2 CH3I (g) → [CH3I]+ (g) ΔrH°(0 K) = 76934 ± 5 cm-1Strobel 1994, Strobel 1993
0.0024381.5 CH3I (g) → [CH3I]+ (g) ΔrH°(0 K) = 76930 ± 20 cm-1Price 1936, est unc
0.0004381.6 CH3I (g) → [CH3I]+ (g) ΔrH°(0 K) = 9.540 ± 0.004 eVKarlsson 1977
0.0004381.7 CH3I (g) → [CH3I]+ (g) ΔrH°(0 K) = 9.533 ± 0.01 eVTsai 1975
0.0004381.8 CH3I (g) → [CH3I]+ (g) ΔrH°(0 K) = 9.550 ± 0.006 (×2) eVNicholson 1965

References (for your convenience, also available in RIS and BibTex format)
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. 1.122g of the Thermochemical Network (2019); available at
4   J. P. Porterfield, D. H. Bross, B. Ruscic, J. H. Thorpe, T. L. Nguyen, J. H. Baraban, J. F. Stanton, J. W. Daily, and G. B. Ellison,
Thermal Decomposition of Potential Ester Biofuels, Part I: Methyl Acetate and Methyl Butanoate.
J. Chem. Phys. A 121, 4658-4677 (2017) [DOI: 10.1021/acs.jpca.7b02639] (Veronica Vaida Festschrift)
5   Y.-C. Chang, B. Xiong, D. H. Bross, B. Ruscic, and C. Y. Ng,
A Vacuum Ultraviolet laser Pulsed Field Ionization-Photoion Study of Methane (CH4): Determination of the Appearance Energy of Methylium From Methane with Unprecedented Precision and the Resulting Impact on the Bond Dissociation Energies of CH4 and CH4+.
Phys. Chem. Chem. Phys. 19, 9592-9605 (2017) [DOI: 10.1039/c6cp08200a] (part of 2017 PCCP Hot Articles collection)
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]

The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.

The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [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.

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.