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].

Iodomethane cation

Formula: [CH3I]+ (g)

CAS RN: 12538-72-6

ATcT ID: 12538-72-6*0

SMILES: C[I+]

InChI: InChI=1S/CH3I/c1-2/h1H3/q+1

InChIKey: NPFPLWGVWWDMKQ-UHFFFAOYSA-N

Hills Formula: C1H3I1+

2D Image:

Aliases: [CH3I]+; Iodomethane cation; Iodomethane ion (1+); Methyl iodide cation; Methyl iodide ion (1+); Methyl monoiodide cation; Methyl monoiodride ion (1+); Monoiodomethane cation; Monoiodomethane ion (1+)

Relative Molecular Mass: 141.93844 ± 0.00083

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
944.71	935.31	± 0.18	kJ/mol

3D Image of [CH3I]+ (g)

spin ON spin OFF

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

The 12 contributors listed below account for 90.3% of the provenance of Δ_fH° 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.

Contribution (%)	TN ID	Reaction	Measured Quantity	Reference
48.5	6222.2	CH3I (g) → [CH3]+ (g) + I (g)	Δ_rH°(0 K) = 12.251 ± 0.0024 eV	Lee 2007
18.4	6222.1	CH3I (g) → [CH3]+ (g) + I (g)	Δ_rH°(0 K) = 12.248 ± 0.003 (×1.297) eV	Bodi 2009, Bodi 2023
5.2	6224.4	CH3I (g) + HI (g) → I2 (g) + CH4 (g)	Δ_rG°(669 K) = -10.34 ± 0.09 (×1.874) kcal/mol	Goy 1965, 3rd Law
4.8	6224.2	CH3I (g) + HI (g) → I2 (g) + CH4 (g)	Δ_rG°(630.5 K) = -10.48 ± 0.08 (×2.181) kcal/mol	Golden 1965, 3rd Law, Cox 1970
3.6	6222.3	CH3I (g) → [CH3]+ (g) + I (g)	Δ_rH°(0 K) = 12.243 ± 0.008 (×1.091) eV	Lee 2007, Bodi 2009
2.4	2359.1	2 H2 (g) + C (graphite) → CH4 (g)	Δ_rG°(1165 K) = 37.521 ± 0.068 kJ/mol	Smith 1946, note COf, 3rd Law
2.0	6222.5	CH3I (g) → [CH3]+ (g) + I (g)	Δ_rH°(0 K) = 12.24 ± 0.01 (×1.164) eV	Mintz 1976
1.5	6235.1	2 CH3I (l) + 7/2 O2 (g) → 2 CO2 (g) + 3 H2O (l) + I2 (cr,l)	Δ_rH°(298.15 K) = -1617.2 ± 0.6 (×4.458) kJ/mol	Carson 1993
0.9	6237.1	2 CH3I (l) + H2 (g) → 2 CH4 (g) + I2 (cr,l)	Δ_rH°(298.15 K) = -30.0 ± 0.8 kcal/mol	Carson 1961, note unc, Cox 1970
0.8	6222.4	CH3I (g) → [CH3]+ (g) + I (g)	Δ_rH°(0 K) = 12.269 ± 0.003 (×5.907) eV	Song 2001
0.8	6224.5	CH3I (g) + HI (g) → I2 (g) + CH4 (g)	Δ_rH°(669 K) = -12.65 ± 0.39 (×1.067) kcal/mol	Goy 1965, 2nd Law
0.8	6155.7	CI4 (g) + 3 CH4 (g) → 4 CH3I (g)	Δ_rH°(0 K) = -6.16 ± 1.0 kcal/mol	xyx 2016

Top 10 species with enthalpies of formation correlated to the Δ_fH° 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.

Correlation Coefficent (%)	Species Name	Formula	Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units	Relative Molecular Mass	ATcT ID
99.7	Iodomethane	CH3I (g)	24.42	14.88	± 0.18	kJ/mol	141.93899 ± 0.00083	74-88-4*0
89.5	Iodomethane	CH3I (l)		-12.26	± 0.20	kJ/mol	141.93899 ± 0.00083	74-88-4*590
25.1	Methylium	[CH3]+ (g)	1099.354	1095.411	± 0.045	kJ/mol	15.03397 ± 0.00083	14531-53-4*0
24.5	Methane	CH4 (g)	-66.541	-74.511	± 0.044	kJ/mol	16.04246 ± 0.00085	74-82-8*0
22.3	Methyl	CH3 (g)	149.882	146.481	± 0.050	kJ/mol	15.03452 ± 0.00083	2229-07-4*0
18.9	Methane cation	[CH4]+ (g)	1150.688	1144.305	± 0.057	kJ/mol	16.04191 ± 0.00085	20741-88-2*0
14.3	Tetraiodomethane	CI4 (g)	320.8	315.7	± 2.0	kJ/mol	519.62858 ± 0.00081	507-25-5*0
11.5	Carbonic acid	C(O)(OH)2 (aq, undissoc)		-698.670	± 0.028	kJ/mol	62.0248 ± 0.0012	463-79-6*1000
11.4	Water	H2O (cr,l)	-286.274	-285.802	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*500
11.4	Water	H2O (l)		-285.802	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*590

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.

Influence Coefficient	TN ID	Reaction	Measured Quantity	Reference
0.904	6221.3	CH3I (g) → [CH3I]+ (g)	Δ_rH°(0 K) = 76930.0 ± 1.0 cm-1	Baig 1981
0.056	6221.1	CH3I (g) → [CH3I]+ (g)	Δ_rH°(0 K) = 76932 ± 4 cm-1	Urban 2002
0.036	6221.2	CH3I (g) → [CH3I]+ (g)	Δ_rH°(0 K) = 76934 ± 5 cm-1	Strobel 1994, Strobel 1993
0.002	6221.5	CH3I (g) → [CH3I]+ (g)	Δ_rH°(0 K) = 76930 ± 20 cm-1	Price 1936, est unc
0.000	6221.6	CH3I (g) → [CH3I]+ (g)	Δ_rH°(0 K) = 9.540 ± 0.004 eV	Karlsson 1977
0.000	6221.7	CH3I (g) → [CH3I]+ (g)	Δ_rH°(0 K) = 9.533 ± 0.01 eV	Tsai 1975
0.000	6221.8	CH3I (g) → [CH3I]+ (g)	Δ_rH°(0 K) = 9.550 ± 0.006 (×2) eV	Nicholson 1965

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. 1.156 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.