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].

Dibromine

Formula: Br2 (g)
CAS RN: 7726-95-6
ATcT ID: 7726-95-6*0
SMILES: BrBr
InChI: InChI=1S/Br2/c1-2
InChIKey: GDTBXPJZTBHREO-UHFFFAOYSA-N
Hills Formula: Br2

2D Image:

BrBr
Aliases: Br2; Dibromine; Bromine molecule; Bromine; Molecular bromine; Diatomic bromine; UN 1744
Relative Molecular Mass: 159.8080 ± 0.0020

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
45.7030.90± 0.11kJ/mol

3D Image of Br2 (g)

spin ON           spin OFF
          

Top contributors to the provenance of ΔfH° of Br2 (g)

The 1 contributors listed below account for 93.1% of the provenance of ΔfH° of Br2 (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
93.11099.2 Br2 (cr,l) → Br2 (g) ΔrH°(298.15 K) = 7.386 ± 0.027 kcal/molHildenbrand 1958

Top 10 species with enthalpies of formation correlated to the ΔfH° of Br2 (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
100.0 Bromine atomBr (g)[Br]117.925111.863± 0.055kJ/mol79.90400 ±
0.00100
10097-32-2*0
100.0 Bromine atomBr (g, 2P3/2)[Br]117.925111.863± 0.055kJ/mol79.90400 ±
0.00100
10097-32-2*1
100.0 Bromine atomBr (g, 2P1/2)[Br]162.009155.947± 0.055kJ/mol79.90400 ±
0.00100
10097-32-2*2
100.0 BromideBr- (g)[Br-]-206.612-212.674± 0.055kJ/mol79.90455 ±
0.00100
24959-67-9*0
99.4 BromanyliumBr+ (g)[Br+]1257.7861251.723± 0.056kJ/mol79.90345 ±
0.00100
22541-56-6*0
93.5 BromochloraneBrCl (g)ClBr21.89114.447± 0.059kJ/mol115.3567 ±
0.0013
13863-41-7*0
83.1 Iodine monobromideIBr (g)BrI49.72740.780± 0.066kJ/mol206.8085 ±
0.0010
7789-33-5*0
48.6 Diatomic bromine cation[Br2]+ (g)Br[Br+]1060.341045.39± 0.23kJ/mol159.8075 ±
0.0020
12595-71-0*0
34.0 Hydrogen bromideHBr (g)Br-27.51-35.36± 0.12kJ/mol80.9119 ±
0.0010
10035-10-6*0
34.0 Bromoniumyl[HBr]+ (g)[BrH+]1098.161090.31± 0.12kJ/mol80.9114 ±
0.0010
12258-64-9*0

Most Influential reactions involving Br2 (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
0.9967427.1 Br2 (g) CH2F2 (g) → HBr (g) CHF2Br (g) ΔrH°(298.15 K) = -9.54 ± 0.07 kcal/molOkafo 1974, as quoted by Cox 1970
0.9311099.2 Br2 (cr,l) → Br2 (g) ΔrH°(298.15 K) = 7.386 ± 0.027 kcal/molHildenbrand 1958
0.8976705.3 CO (g) Br2 (g) → CBr2O (g) ΔrG°(444 K) = 6.169 ± 0.088 kcal/molDunning 1972, 3rd Law
0.8211100.13 Br2 (g) → 2 Br (g) ΔrH°(0 K) = 15895.537 ± 0.020 cm-1Gerstenkorn 1989, Br 79.90
0.8046278.1 Br2 (g) CHCl3 (g) → HBr (g) CCl3Br (g) ΔrH°(298.15 K) = -1.41 ± 0.10 kcal/molMendenhall 1973, as quoted by Pedley 1986
0.7896489.2 CF3CF3 (g) Br2 (g) → 2 CF3Br (g) ΔrG°(670.8 K) = -1.58 ± 0.62 kJ/molCoomber 1967a, 3rd Law
0.7627457.1 CH2CH2 (g) Br2 (g) → CH2BrCH2Br (g) ΔrH°(355 K) = -29.058 ± 0.300 kcal/molConn 1938
0.7061213.6 BrCl (g) → Br2 (g) Cl2 (g) ΔrG°(295.15 K) = 5.419 ± 0.049 kJ/molTellinghuisen 2003, 3rd Law
0.5861114.1 Br- (g) Br2 (g) → [Br2]- (g) Br (g) ΔrH°(0 K) = 0.84 ± 0.03 eVChupka 1971b
0.5276283.1 CHBr3 (g) Br2 (g) → CBr4 (g) HBr (g) ΔrG°(588.3 K) = 3.27 ± 1.00 kJ/molKing 1971, 3rd Law
0.4581102.1 Br2 (g) → [Br2]+ (g) ΔrH°(0 K) = 10.518 ± 0.003 eVYencha 1995
0.2891197.4 [Br3]- (g) → Br- (g) Br2 (g) ΔrH°(298.15 K) = 30.6 ± 0.8 kcal/molThanthiriwatte 2014, est unc
0.2461283.1 I- (g) Br2 (g) → [Br2]- (g) I (g) ΔrH°(0 K) = 0.59 ± 0.03 (×1.542) eVChupka 1971b
0.2021196.1 Br3 (g) → Br2 (g) Br (g) ΔrH°(0 K) = 13 ± 7 kJ/molKawasaki 1989
0.1845928.1 CCl3 (g) Br2 (g) → CCl3Br (g) Br (g) ΔrG°(437 K) = -3.5 ± 0.5 kcal/molHudgens 1991, 3rd Law
0.1651102.2 Br2 (g) → [Br2]+ (g) ΔrH°(0 K) = 10.515 ± 0.005 eVvan Lonkhuyzen 1984
0.1651102.7 Br2 (g) → [Br2]+ (g) ΔrH°(0 K) = 10.516 ± 0.005 eVRuscic 1994
0.1386277.1 Br2 (g) CCl4 (g) → BrCl (g) CCl3Br (g) ΔrH°(298.15 K) = 8.84 ± 0.30 kcal/molMendenhall 1973, as quoted by Pedley 1986
0.1171211.9 BrCl (g) → Br2 (g) Cl2 (g) ΔrG°(301.15 K) = 5.54 ± 0.12 kJ/molVesper 1934, 3rd Law, est unc
0.0976255.1 CF3Cl (g) Br2 (g) → CF3Br (g) BrCl (g) ΔrH°(298.15 K) = 10.49 ± 0.40 (×1.114) kcal/molCoomber 1967b, as quoted by Cox 1970


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.