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II.A.1. (XV.A.)

Listing of experimental data for Br2 (Bromine diatomic)

Other names
UN 1744; Dibromine; Broom; Brome; Bromo; Brom;
INChI SMILES IUPAC name
InChI=1/Br2/c1-2 BrBr Dibromine
State Conformation
1Σg D*H
Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)
Property Value Uncertainty units Reference Comment
Hfg(298.15K) enthalpy of formation 30.91 0.11 kJ mol-1 CODATA
Hfg(0K) enthalpy of formation 45.71 0.11 kJ mol-1 CODATA
Entropy (298.15K) entropy 245.47 0.00 J K-1 mol-1 CODATA
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity 9.73 0.00 kJ mol-1 CODATA
Heat Capacity (298.15K) heat capacity 36.05   J K-1 mol-1 JANAF
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency (cm-1) Frequency Reference Intensity (km mol-1) Int. unc. Intensity Reference Comment
1 Σ 325 webbook       omega e

vibrational zero-point energy: 162.7 cm-1
Calculated vibrational frequencies for Br2 (Bromine diatomic).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  0.08211   webbook Be

Calculated rotational constants for Br2 (Bromine diatomic).

Product of moments of inertia moments of inertia
205.313amu Å2   3.409355E-38gm cm2

Geometric Data
picture of Bromine diatomic

Point Group D∞h

Internal coordinates
distances (r) in Å, angles (a) in degrees, dihedrals (d) in degrees
Description Value unc. Connectivity Reference Comment
Atom 1 Atom 2 Atom 3 Atom 4
rBrBr 2.281   1 2 webbook re

Cartesians
Atom x (Å) y (Å) z (Å)
Br1 0.0000 0.0000 1.1405
Br2 0.0000 0.0000 -1.1405

Atom - Atom Distances bond lengths
Distances in Å
  Br1 Br2
Br1   2.2811
Br2 2.2811  

Calculated geometries for Br2 (Bromine diatomic).

Bond descriptions
Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
Br-Br 1

Connectivity
Atom 1 Atom 2
Br1 Br2

Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1   1Σg
13905 6 webbook
15902.47 6 webbook
24000 2 webbook

Ionization Energies (eV)
Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
10.517 0.003     webbook

Electron Affinity (eV)
Electron Affinity unc. reference
2.420   webbook

Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
For a molecule with D∞h symmetry there is no dipole.
Electric quadrupole moment quadrupole
Calculated electric quadrupole moments for Br2 (Bromine diatomic).

References
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squib reference DOI
CODATA Cox, J.D.; Wagman, D.D.; Medvedev, V.A.CODATA Key Values for Thermodynamics. Hemisphere, New York, 1989  
JANAF Chase, M.W., Jr.; Davies, C.A.; Downey, J.R., Jr.; Frurip, D.J.; McDonald, R.A.; Syverud, A.N., JANAF Thermochemical Tables (Third Edition), J. Phys. Chem. Ref. Data,Suppl. 1, 1985, 14, 1.  
webbook NIST Chemistry Webbook (http://webbook.nist.gov/chemistry)  

Got a better number? Please email us at cccbdb@nist.gov


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