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].

Dibromomethane

Formula: CH2Br2 (g)

CAS RN: 74-95-3

ATcT ID: 74-95-3*0

SMILES: C(Br)Br

InChI: InChI=1S/CH2Br2/c2-1-3/h1H2

InChIKey: FJBFPHVGVWTDIP-UHFFFAOYSA-N

Hills Formula: C1H2Br2

2D Image:

Aliases: CH2Br2; Dibromomethane; Methylene bromide; Methylene dibromide; Methane dibromide; Carbon dibromide; Dibromocarbon; RCRA U068; UN 2664

Relative Molecular Mass: 173.8346 ± 0.0022

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
27.03	5.62	± 0.64	kJ/mol

3D Image of CH2Br2 (g)

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Top contributors to the provenance of Δ_fH° of CH2Br2 (g)

The 20 contributors listed below account only for 69.8% of the provenance of Δ_fH° of CH2Br2 (g).
A total of 45 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
13.4	6476.6	CH4 (g) + CBr4 (g) → 2 CH2Br2 (g)	Δ_rH°(0 K) = -24.6 ± 2.5 kJ/mol	Bross 2023
6.1	6405.8	CH2Br2 (g) → C (g) + 2 H (g) + 2 Br (g)	Δ_rH°(0 K) = 1352.2 ± 2.5 kJ/mol	Bross 2023
5.5	6407.2	CH2Br2 (g) + 2 H2 (g) → CH4 (g) + 2 HBr (g)	Δ_rH°(0 K) = -148.5 ± 2.5 kJ/mol	Bross 2023
5.3	6478.6	CH3Br (g) + CBr4 (g) → CH2Br2 (g) + CHBr3 (g)	Δ_rH°(0 K) = -17.1 ± 2.5 kJ/mol	Bross 2023
5.0	6408.2	CH2Br2 (g) + H2 (g) → CH3Br (g) + HBr (g)	Δ_rH°(0 K) = -74.8 ± 2.5 kJ/mol	Bross 2023
4.5	6411.2	CH2Br2 (g) + CH4 (g) → 2 CH3Br (g)	Δ_rH°(0 K) = -1.1 ± 2.5 kJ/mol	Bross 2023
4.5	6474.7	CH4 (g) + CH2Br2 (g) → 2 CH3Br (g)	Δ_rH°(0 K) = -1.1 ± 2.5 kJ/mol	Bross 2023
3.0	6406.1	CH2Br2 (g) + 2 Cl (g) → CH2Cl2 (g) + 2 Br (g)	Δ_rH°(0 K) = -1.209 ± 0.035 eV	Lago 2005
2.6	6435.1	CH2ClBr (g) + Br (g) → CH2Br2 (g) + Cl (g)	Δ_rH°(0 K) = 0.583 ± 0.032 eV	Lago 2005
2.3	6413.2	CH2Br2 (g) + 2 CH3Br (g) → CBr4 (g) + 2 CH4 (g)	Δ_rH°(0 K) = 25.7 ± 2.5 kJ/mol	Bross 2023
2.0	1108.2	Br2 (cr,l) → Br2 (g)	Δ_rH°(298.15 K) = 7.386 ± 0.027 kcal/mol	Hildenbrand 1958
1.8	6412.2	CH2Br2 (g) + CH3Br (g) → CHBr3 (g) + CH4 (g)	Δ_rH°(0 K) = 7.5 ± 2.5 kJ/mol	Bross 2023
1.8	6475.6	CH4 (g) + CHBr3 (g) → CH2Br2 (g) + CH3Br (g)	Δ_rH°(0 K) = -7.5 ± 2.5 kJ/mol	Bross 2023
1.7	6410.2	CH2Br2 (g) + 2 HBr (g) → CBr4 (g) + 2 H2 (g)	Δ_rH°(0 K) = 173.1 ± 2.5 kJ/mol	Bross 2023
1.6	6474.4	CH4 (g) + CH2Br2 (g) → 2 CH3Br (g)	Δ_rH°(0 K) = 0.28 ± 1.0 kcal/mol	Ruscic G4
1.6	6409.2	CH2Br2 (g) + HBr (g) → CHBr3 (g) + H2 (g)	Δ_rH°(0 K) = 81.2 ± 2.5 kJ/mol	Bross 2023
1.6	6235.8	CBr4 (g) → C (g) + 4 Br (g)	Δ_rH°(0 K) = 1037.9 ± 2.5 kJ/mol	Bross 2023
1.5	6369.7	CHBr3 (g) → C (g) + H (g) + 3 Br (g)	Δ_rH°(0 K) = 1200.4 ± 2.5 kJ/mol	Bross 2023
1.5	6236.6	CBr4 (g) + 4 H (g) → CH4 (g) + 4 Br (g)	Δ_rH°(0 K) = -604.0 ± 2.5 kJ/mol	Bross 2023
1.5	6478.4	CH3Br (g) + CBr4 (g) → CH2Br2 (g) + CHBr3 (g)	Δ_rH°(0 K) = -2.81 ± 1.0 (×1.091) kcal/mol	Ruscic G4

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH2Br2 (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
48.3	Bromoform	CHBr3 (g)	80.92	54.77	± 0.71	kJ/mol	252.7306 ± 0.0031	75-25-2*0
47.8	Bromoform	CHBr3 (l)		8.73	± 0.72	kJ/mol	252.7306 ± 0.0031	75-25-2*590
47.5	Tetrabromomethane	CBr4 (g)	144.72	115.02	± 0.74	kJ/mol	331.6267 ± 0.0041	558-13-4*0
36.6	Tetrabromomethane	CBr4 (cr, monoclinic)		60.54	± 0.96	kJ/mol	331.6267 ± 0.0041	558-13-4*500
27.5	Bromomethane	CH3Br (g)	-20.48	-35.88	± 0.19	kJ/mol	94.9385 ± 0.0013	74-83-9*0
26.7	Bromomethane cation	[CH3Br]+ (g)	996.63	981.72	± 0.20	kJ/mol	94.9380 ± 0.0013	12538-70-4*0
26.1	Bromomethane	CH3Br (l)	-56.20	-59.22	± 0.20	kJ/mol	94.9385 ± 0.0013	74-83-9*590
20.5	Hydrogen bromide	HBr (g)	-27.52	-35.36	± 0.12	kJ/mol	80.9119 ± 0.0010	10035-10-6*0
20.5	Bromoniumyl	[HBr]+ (g)	1098.16	1090.31	± 0.12	kJ/mol	80.9114 ± 0.0010	12258-64-9*0
18.9	Tribromochloromethane	CBr3Cl (g)	86.7	63.8	± 1.4	kJ/mol	287.1754 ± 0.0032	594-15-0*0

Most Influential reactions involving CH2Br2 (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
0.202	6476.6	CH4 (g) + CBr4 (g) → 2 CH2Br2 (g)	Δ_rH°(0 K) = -24.6 ± 2.5 kJ/mol	Bross 2023
0.185	6435.1	CH2ClBr (g) + Br (g) → CH2Br2 (g) + Cl (g)	Δ_rH°(0 K) = 0.583 ± 0.032 eV	Lago 2005
0.164	6479.6	CH2Br2 (g) + CBr4 (g) → 2 CHBr3 (g)	Δ_rH°(0 K) = -10.7 ± 2.5 kJ/mol	Bross 2023
0.107	6478.6	CH3Br (g) + CBr4 (g) → CH2Br2 (g) + CHBr3 (g)	Δ_rH°(0 K) = -17.1 ± 2.5 kJ/mol	Bross 2023
0.086	6413.2	CH2Br2 (g) + 2 CH3Br (g) → CBr4 (g) + 2 CH4 (g)	Δ_rH°(0 K) = 25.7 ± 2.5 kJ/mol	Bross 2023
0.079	6410.2	CH2Br2 (g) + 2 HBr (g) → CBr4 (g) + 2 H2 (g)	Δ_rH°(0 K) = 173.1 ± 2.5 kJ/mol	Bross 2023
0.074	6412.2	CH2Br2 (g) + CH3Br (g) → CHBr3 (g) + CH4 (g)	Δ_rH°(0 K) = 7.5 ± 2.5 kJ/mol	Bross 2023
0.074	6475.6	CH4 (g) + CHBr3 (g) → CH2Br2 (g) + CH3Br (g)	Δ_rH°(0 K) = -7.5 ± 2.5 kJ/mol	Bross 2023
0.073	6409.2	CH2Br2 (g) + HBr (g) → CHBr3 (g) + H2 (g)	Δ_rH°(0 K) = 81.2 ± 2.5 kJ/mol	Bross 2023
0.065	6474.7	CH4 (g) + CH2Br2 (g) → 2 CH3Br (g)	Δ_rH°(0 K) = -1.1 ± 2.5 kJ/mol	Bross 2023
0.065	6411.2	CH2Br2 (g) + CH4 (g) → 2 CH3Br (g)	Δ_rH°(0 K) = -1.1 ± 2.5 kJ/mol	Bross 2023
0.063	6405.8	CH2Br2 (g) → C (g) + 2 H (g) + 2 Br (g)	Δ_rH°(0 K) = 1352.2 ± 2.5 kJ/mol	Bross 2023
0.063	6407.2	CH2Br2 (g) + 2 H2 (g) → CH4 (g) + 2 HBr (g)	Δ_rH°(0 K) = -148.5 ± 2.5 kJ/mol	Bross 2023
0.060	6408.2	CH2Br2 (g) + H2 (g) → CH3Br (g) + HBr (g)	Δ_rH°(0 K) = -74.8 ± 2.5 kJ/mol	Bross 2023
0.058	6479.4	CH2Br2 (g) + CBr4 (g) → 2 CHBr3 (g)	Δ_rH°(0 K) = -2.00 ± 1.0 kcal/mol	Ruscic G4
0.048	6479.3	CH2Br2 (g) + CBr4 (g) → 2 CHBr3 (g)	Δ_rH°(0 K) = -2.21 ± 1.1 kcal/mol	Ruscic G3X
0.040	6406.1	CH2Br2 (g) + 2 Cl (g) → CH2Cl2 (g) + 2 Br (g)	Δ_rH°(0 K) = -1.209 ± 0.035 eV	Lago 2005
0.032	6478.4	CH3Br (g) + CBr4 (g) → CH2Br2 (g) + CHBr3 (g)	Δ_rH°(0 K) = -2.81 ± 1.0 (×1.091) kcal/mol	Ruscic G4
0.031	6478.3	CH3Br (g) + CBr4 (g) → CH2Br2 (g) + CHBr3 (g)	Δ_rH°(0 K) = -2.99 ± 1.1 kcal/mol	Ruscic G3X
0.023	6474.4	CH4 (g) + CH2Br2 (g) → 2 CH3Br (g)	Δ_rH°(0 K) = 0.28 ± 1.0 kcal/mol	Ruscic G4

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.