Bromine

• Formula: Br₂
• Molecular weight: 159.808
• IUPAC Standard InChI: InChI=1S/Br2/c1-2 Copy

  
• IUPAC Standard InChIKey: GDTBXPJZTBHREO-UHFFFAOYSA-N Copy
• CAS Registry Number: 7726-95-6
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
  The 3d structure may be viewed using Java or Javascript.
• Other names: Br2; Brom; Brome; Bromo; Broom; UN 1744; Dibromine
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Phase change data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 55
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • Constants of diatomic molecules
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
• Options:
  • Switch to SI units

Data at NIST subscription sites:

• NIST / TRC Web Thermo Tables, "lite" edition (thermophysical and thermochemical data)
• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Gas phase thermochemistry data

Go To: Top, Phase change data, Gas phase ion energetics data, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
    C_p = heat capacity (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

View table.

Phase change data

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos

Enthalpy of vaporization

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Phase change data, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data evaluated as indicated in comments:
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to Br₂⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

Appearance energy determinations

Anion protonation reactions

 +  =

By formula: Br^- + H⁺ = HBr

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A., CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Weber, 1912
Weber, H.C.P., J. Am. Chem. Soc., 1912, 34, 1294. [all data]

Serullas, 1827
Serullas, New Compounds of Bromine. Ethyl Bromide ("Ether Hydro-Bromique"), and Cyanogen Bromide ("Cyanure de Brome"). Solidification of Bromine and of Bromform ("Hydro-carbure de Brome"), Ann. Chim. Phys., 1827, 34, 95. [all data]

Blair and Ihle, 1973
Blair, A.; Ihle, H., The thermal decomposition and thermodynamic properties of uranium pentabromide, Journal of Inorganic and Nuclear Chemistry, 1973, 35, 11, 3795-3803, https://doi.org/10.1016/0022-1902(73)80071-5 . [all data]

Fischer and Bingle, 1955
Fischer, Jack; Bingle, James, The Vapor Pressure of Bromine from 24 to 116° ¹, J. Am. Chem. Soc., 1955, 77, 24, 6511-6512, https://doi.org/10.1021/ja01629a026 . [all data]

Giauque and Wiebe, 1928
Giauque, W.F.; Wiebe, R., THE HEAT CAPACITY OF HYDROGEN BROMIDE FROM 15°K. TO ITS BOILING POINT AND ITS HEAT OF VAPORIZATION. THE ENTROPY FROM SPECTROSCOPIC DATA, J. Am. Chem. Soc., 1928, 50, 8, 2193-2202, https://doi.org/10.1021/ja01395a018 . [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Ayala, Wentworth, et al., 1981
Ayala, J.A.; Wentworth, W.E.; Chen, E.C.M., Electron attachment to halogens, J. Phys. Chem., 1981, 85, 768. [all data]

Dispert and Lacmann, 1977
Dispert, H.; Lacmann, K., Chemiionization in alkali-halogen reactions: Evidence for ion formation by alkali dimers, Chem. Phys. Lett., 1977, 47, 533. [all data]

Hughes, Lifschitz, et al., 1973
Hughes, B.M.; Lifschitz, C.; Tiernan, T.O., Electron affinities from endothermic negative-ion charge-transfer reactions. III. NO, NO₂, S₂, CS₂, Cl₂, Br₂, I₂, and C₂H, J. Chem. Phys., 1973, 59, 3162. [all data]

Baeda, 1972
Baeda, A.P.M., The adiabatic electron affinities of Cl₂, Br₂, I₂, IBr, NO₂, and O₂, Physica, 1972, 59, 541. [all data]

Chupka, Berkowitz, et al., 1971
Chupka, W.A.; Berkowitz, J.; Gutman, D., Electron Affinities of Halogen Diatomic Molecules as Determined by Endoergic Charge Exchange, J. Chem. Phys., 1971, 55, 6, 2724, https://doi.org/10.1063/1.1676487 . [all data]

DeCorpo and Franklin, 1971
DeCorpo, J.J.; Franklin, J.L., Electron affinities of the halogen molecules by dissociative electron attachment, J. Chem. Phys., 1971, 54, 1885. [all data]

Hubers, Kleyn, et al., 1976
Hubers, M.M.; Kleyn, A.W.; Los, J., Ion pair formation in alkali-halogen collisions at high velocities, Chem. Phys., 1976, 17, 303. [all data]

Yencha, Hopkirk, et al., 1995
Yencha, A.J.; Hopkirk, A.; Hiraya, A.; Donovan, R.J.; Goode, J.G.; Maier, R.R.J.; King, G.C.; Kvaran, A., Threshold photoelectron spectroscopy of Cl₂ and Br₂ up to 35 eV, J. Phys. Chem., 1995, 99, 7231. [all data]

Ruscic and Berkowitz, 1994
Ruscic, B.; Berkowitz, J., Threshold photoelectron spectrum of HOBr, J. Chem. Phys., 1994, 101, 9215. [all data]

Monks, Stief, et al., 1994
Monks, P.S.; Stief, L.J.; Krauss, M.; Kuo, S.C.; Klemm, R.B., A discharge flow-photoionization mass spectrometric study of HOBr (X<1>A'): Photoion yield spectrum, ionization energy, and thermochemistry, J. Chem. Phys., 1994, 100, 1902. [all data]

Lau and Hildenbrand, 1987
Lau, K.H.; Hildenbrand, D.L., Thermochemistry of the gaseous uranium bromides UBr through UBr₅(a), J. Chem. Phys., 1987, 86, 2949. [all data]

Van Lonkhuyzen and De Lange, 1984
Van Lonkhuyzen, H.; De Lange, C.A., High-resolution UV photoelectron spectroscopy of diatomic halogens, Chem. Phys., 1984, 89, 313. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Huber and Herzberg, 1979
Huber, K.P.; Herzberg, G., Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules,, Van Nostrand Reinhold Co., 1979, ,1. [all data]

Kaposi, Popovic, et al., 1977
Kaposi, O.; Popovic, A.; Marsel, J., Mass spectrometric studies of tungsten bromides and oxybromides, J. Inorg. Nucl. Chem., 1977, 39, 1809. [all data]

Potts and Price, 1971
Potts, A.W.; Price, W.C., Photoelectron spectra of the halogens and mixed halides ICI and lBr, J. Chem. Soc. Faraday Trans., 1971, 67, 1242. [all data]

Cornford, Frost, et al., 1971
Cornford, A.B.; Frost, D.C.; McDowell, C.A.; Ragle, J.L.; Stenhouse, I.A., Photoelectron spectra of the halogens, J. Chem. Phys., 1971, 54, 2651. [all data]

Dibeler, Walker, et al., 1970
Dibeler, V.H.; Walker, J.A.; McCulloh, K.E., Threshold for molecular photoionization of bromine, J. Chem. Phys., 1970, 53, 4715. [all data]

Venkateswarlu, 1968
Venkateswarlu, P., Vacuum ultraviolet spectrum of bromine molecule, Bull. Am. Phys. Soc., 1968, 13, 1666. [all data]

Dyke, Josland, et al., 1984
Dyke, J.M.; Josland, G.D.; Snijders, J.G.; Boerrigter, P.M., Ionization energies of the diatomic halogens and interhalogens studied with relativistic hartree-fock-slater calculations, Chem. Phys., 1984, 91, 419. [all data]

Utsunomiya, Kobayashi, et al., 1976
Utsunomiya, C.; Kobayashi, T.; Nagakura, S., Photoelectron spectra of electron donor-acceptor complexes between bromine and alkylamines, Chem. Phys. Lett., 1976, 39, 245. [all data]

Morrison, Hurzeler, et al., 1960
Morrison, J.D.; Hurzeler, H.; Inghram, M.G.; Stanton, H.E., Threshold law for the probability of excitation of molecules by photon impact. A study of the photoionization efficiencies of Br₂, I₂, HI, and CH₃I, J. Chem. Phys., 1960, 33, 821. [all data]

Frost and McDowell, 1960
Frost, D.C.; McDowell, C.A., The ionization and dissociation of some halogen molecules by electron impact, Can. J. Chem., 1960, 38, 407. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Blondel, Cacciani, et al., 1989
Blondel, C.; Cacciani, P.; Delsart, C.; Trainham, R., High Resolution Determination of the Electron Affinity of Fluorine and Bromine using Crossed Ion and Laser Beams, Phys. Rev. A, 1989, 40, 7, 3698, https://doi.org/10.1103/PhysRevA.40.3698 . [all data]

Taft and Bordwell, 1988
Taft, R.W.; Bordwell, F.G., Structural and Solvent Effects Evaluated from Acidities Measured in Dimethyl Sulfoxide and in the Gas Phase, Acc. Chem. Res., 1988, 21, 12, 463, https://doi.org/10.1021/ar00156a005 . [all data]

Check, Faust, et al., 2001
Check, C.E.; Faust, T.O.; Bailey, J.M.; Wright, B.J.; Gilbert, T.M.; Sunderlin, L.S., Addition of Polarization and Diffuse Functions to the LANL2DZ Basis Set for P-Block Elements, J. Phys. Chem. A,, 2001, 105, 34, 8111, https://doi.org/10.1021/jp011945l . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  AE	Appearance energy
  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  Tfus	Fusion (melting) point
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔvapH	Enthalpy of vaporization

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
• The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
• Customer support for NIST Standard Reference Data products.