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].

Bromomethane cation

Formula: [CH3Br]+ (g)

CAS RN: 12538-70-4

ATcT ID: 12538-70-4*0

SMILES: C[Br+]

InChI: InChI=1S/CH3Br/c1-2/h1H3/q+1

InChIKey: UCZMPBXSFVNQCY-UHFFFAOYSA-N

Hills Formula: C1H3Br1+

2D Image:

Aliases: [CH3Br]+; Bromomethane cation; Bromomethane ion (1+); Methyl bromide cation; Methyl bromide ion (1+); Methyl monobromide cation; Methyl monobromride ion (1+); Monobromomethane cation; Monobromomethane ion (1+)

Relative Molecular Mass: 94.9380 ± 0.0013

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
996.63	981.72	± 0.20	kJ/mol

3D Image of [CH3Br]+ (g)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of [CH3Br]+ (g)

The 20 contributors listed below account only for 55.4% of the provenance of Δ_fH° of [CH3Br]+ (g).
A total of 268 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
9.6	6283.6	4 CH3Cl (g) → CCl4 (g) + 3 CH4 (g)	Δ_rH°(0 K) = 2.52 ± 0.30 kcal/mol	Karton 2017
8.5	6290.1	CH3Br (g) → [CH3]+ (g) + Br (g)	Δ_rH°(0 K) = 12.834 ± 0.002 (×2.828) eV	Song 2001
5.2	6288.1	CH3Br (g) → [CH3Br]+ (g)	Δ_rH°(0 K) = 85024.6 ± 4 cm-1	Urban 2002
4.8	1108.2	Br2 (cr,l) → Br2 (g)	Δ_rH°(298.15 K) = 7.386 ± 0.027 kcal/mol	Hildenbrand 1958
3.7	9678.1	S(O)(OH)2 (aq, 2500 H2O) + Br2 (cr,l) + H2O (cr,l) → OS(O)(OH)2 (aq, 2500 H2O) + 2 HBr (aq, 1250 H2O)	Δ_rH°(298.15 K) = -55.47 ± 0.11 kcal/mol	Johnson 1963
2.6	6468.7	CH4 (g) + CH2Cl2 (g) → 2 CH3Cl (g)	Δ_rH°(0 K) = 1.03 ± 0.25 kcal/mol	Karton 2017, Karton 2011, Karton 2007, Karton 2006
2.5	6304.13	4 CH3Br (g) → CBr4 (g) + 3 CH4 (g)	Δ_rH°(0 K) = 26.8 ± 2.5 kJ/mol	Bross 2023
2.4	1209.1	[HBr]+ (g) → H (g) + Br+ (g)	Δ_rH°(0 K) = 31394.5 ± 20 cm-1	Haugh 1971, Norling 1935
2.1	6323.5	4 CH3I (g) + CBr4 (g) → 4 CH3Br (g) + CI4 (g)	Δ_rH°(0 K) = -0.5 ± 2.5 kJ/mol	Bross 2023
2.0	6274.1	CH3Cl (g) + 3/2 O2 (g) → CO2 (g) + H2O (cr,l) + HCl (aq, 600 H2O)	Δ_rH°(298.15 K) = -764.00 ± 0.50 (×1.756) kJ/mol	Fletcher 1971
1.5	6292.3	CH3Br (g) + HBr (g) → Br2 (g) + CH4 (g)	Δ_rG°(712.2 K) = 35.8 ± 1.6 kJ/mol	Ferguson 1973, 3rd Law
1.4	2375.1	2 H2 (g) + C (graphite) → CH4 (g)	Δ_rG°(1165 K) = 37.521 ± 0.068 kJ/mol	Smith 1946, note COf, 3rd Law
1.3	6308.1	2 CH3Br (l) + H2 (g) → 2 CH4 (g) + Br2 (cr,l)	Δ_rH°(298.15 K) = -6.60 ± 0.60 (×1.189) kcal/mol	Adams 1966, as quoted by Cox 1970
1.3	6471.6	CH4 (g) + CCl4 (g) → CH3Cl (g) + CHCl3 (g)	Δ_rH°(0 K) = -3.24 ± 0.25 kcal/mol	Karton 2017, Karton 2011, Karton 2007, Karton 2006
1.0	6376.6	CHBr3 (g) + 2 CH4 (g) → 3 CH3Br (g)	Δ_rH°(0 K) = -8.6 ± 2.5 kJ/mol	Bross 2023
1.0	6277.10	CH3Cl (g) + H (g) → CH4 (g) + Cl (g)	Δ_rH°(0 K) = -7296 ± 100 cm-1	Czako 2012
0.9	6235.8	CBr4 (g) → C (g) + 4 Br (g)	Δ_rH°(0 K) = 1037.9 ± 2.5 kJ/mol	Bross 2023
0.9	6249.5	CI4 (g) + 4 Br (g) → CBr4 (g) + 4 I (g)	Δ_rH°(0 K) = -221.5 ± 2.5 kJ/mol	Bross 2023
0.9	6469.7	CH4 (g) + CHCl3 (g) → CH2Cl2 (g) + CH3Cl (g)	Δ_rH°(0 K) = -0.13 ± 0.25 kcal/mol	Karton 2017, Karton 2011, Karton 2007, Karton 2006
0.9	6236.6	CBr4 (g) + 4 H (g) → CH4 (g) + 4 Br (g)	Δ_rH°(0 K) = -604.0 ± 2.5 kJ/mol	Bross 2023

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [CH3Br]+ (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
97.1	Bromomethane	CH3Br (g)	-20.48	-35.88	± 0.19	kJ/mol	94.9385 ± 0.0013	74-83-9*0
92.1	Bromomethane	CH3Br (l)	-56.20	-59.22	± 0.20	kJ/mol	94.9385 ± 0.0013	74-83-9*590
77.6	Chloromethane	CH3Cl (g)	-74.67	-82.60	± 0.17	kJ/mol	50.4872 ± 0.0012	74-87-3*0
76.8	Chloromethane cation	[CH3Cl]+ (g)	1014.61	1007.84	± 0.17	kJ/mol	50.4867 ± 0.0012	12538-71-5*0
76.1	Chloromethane	CH3Cl (l)	-106.46	-102.50	± 0.17	kJ/mol	50.4872 ± 0.0012	74-87-3*590
44.3	Hydrogen bromide	HBr (g)	-27.52	-35.36	± 0.12	kJ/mol	80.9119 ± 0.0010	10035-10-6*0
44.3	Bromoniumyl	[HBr]+ (g)	1098.16	1090.31	± 0.12	kJ/mol	80.9114 ± 0.0010	12258-64-9*0
40.4	Hydrogen bromide	HBr (aq, 2570 H2O)		-120.24	± 0.12	kJ/mol	80.9119 ± 0.0010	10035-10-6*952
40.4	Hydrogen bromide	HBr (aq, 3000 H2O)		-120.26	± 0.12	kJ/mol	80.9119 ± 0.0010	10035-10-6*842
40.4	Hydrogen bromide	HBr (aq, 600 H2O)		-120.01	± 0.12	kJ/mol	80.9119 ± 0.0010	10035-10-6*834

Most Influential reactions involving [CH3Br]+ (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
0.916	6288.1	CH3Br (g) → [CH3Br]+ (g)	Δ_rH°(0 K) = 85024.6 ± 4 cm-1	Urban 2002
0.036	6288.2	CH3Br (g) → [CH3Br]+ (g)	Δ_rH°(0 K) = 85017.0 ± 20 cm-1	Baig 1982, est unc
0.036	6288.4	CH3Br (g) → [CH3Br]+ (g)	Δ_rH°(0 K) = 85020 ± 20 cm-1	Price 1936, est unc
0.006	6288.5	CH3Br (g) → [CH3Br]+ (g)	Δ_rH°(0 K) = 10.543 ± 0.006 eV	Karlsson 1977
0.002	6288.6	CH3Br (g) → [CH3Br]+ (g)	Δ_rH°(0 K) = 10.54 ± 0.01 eV	Tsai 1975
0.001	6288.7	CH3Br (g) → [CH3Br]+ (g)	Δ_rH°(0 K) = 10.528 ± 0.005 (×2.768) 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. 1.176 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.