Bromine: isotope data

Both Bromine isotopes are used in nuclear medicine. Br-81 is used for the production of the radioisotope Kr-81m which is used for diagnostics. Br-79 can be used for the cyclotron production of Kr-77 which decays to the radioisotope Br-77 although the most common production route for Br-77 is via Se-77. Br-77 has been suggested for radiotherapy because of it electron capture decay and ease of labeling.

Naturally occurring isotopes

This table shows information about naturally occuring isotopes, their atomic masses, their natural abundances, their nuclear spins, and their magnetic moments. Further data for radioisotopes (radioactive isotopes) of bromine are listed (including any which occur naturally) below.
Isotope Mass / Da Natural abundance (atom %) Nuclear spin (I) Magnetic moment (μ/μN)
79Br 78.9183361 (26) 50.69 (7) 3/2 2.106399
81Br 80.916289 (6) 49.31 (7) 3/2 2.270560

In the above, the most intense ion is set to 100% since this corresponds best to the output from a mass spectrometer. This is not to be confused with the relative percentage isotope abundances which totals 100% for all the naturally occurring isotopes.

Radiosotope data

Further data for naturally occuring isotopes of bromine are listed above. This table gives information about some radiosotopes of bromine, their masses, their half-lives, their modes of decay, their nuclear spins, and their nuclear magnetic moments.
Isotope Mass / Da Half-life Mode of decay Nuclear spin Nuclear magnetic moment
72Br 71.9365 1.31 m EC to 72Se 3
73Br 72.9318 3.4 m EC to 73Se 3/2
74Br 73.92989 25.4 m EC to 74Se
75Br 74.92578 1.62 h EC to 75Se 3/2 0.75
76Br 75.92454 16.0 h EC to 76Se 1 0.54821
77Br 76.921380 2.376 d EC to 77Se 3/2
78Br 77.921146 6.46 m EC to 78Se; β- to 78Kr 1 0.1
80Br 79.918530 17.66 m EC to 80Se; β- to 80Kr 1 0.5140
82Br 81.916805 1.471 d β- to 82Kr 5 1.6270
83Br 82.915181 2.40 h β- to 83Kr 3/2
84Br 83.91651 31.8 m β- to 84Kr 2
85Br 84.91561 2.87 m β- to 85Kr 3/2

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  1. Naturally occurring isotope abundances: Commission on Atomic Weights and Isotopic Abundances report for the International Union of Pure and Applied Chemistry in Isotopic Compositions of the Elements 1989, Pure and Applied Chemistry, 1998, 70, 217. [Copyright 1998 IUPAC]
  2. For further information about radioisotopes see Jonghwa Chang's (Korea Atomic Energy Research Institute) Table of the Nuclides
  3. Masses, nuclear spins, and magnetic moments: I. Mills, T. Cvitas, K. Homann, N. Kallay, and K. Kuchitsu in Quantities, Units and Symbols in Physical Chemistry, Blackwell Scientific Publications, Oxford, UK, 1988. [Copyright 1988 IUPAC]

NMR Properties of bromine

Common reference compound: NaBr/D2O.

Table of NMR-active nucleus propeties of bromine
  Isotope 1 Isotope 2 Isotope 3
Isotope 79Br 81Br
Natural abundance /% 50.69 49.31
Spin (I) 3/2 3/2
Frequency relative to 1H = 100 (MHz) 25.054452 27.007026
Receptivity, DP, relative to 1H = 1.00 0.0403 0.0491
Receptivity, DC, relative to 13C = 1.00 230 280
Magnetogyric ratio, γ (107 rad T‑1 s-1) 6.725616 7.249776
Magnetic moment, μ (μN) 2.719351 2.931283
Nuclear quadrupole moment, Q/millibarn 313(3) 261.5(25)
Line width factor, 1056 l (m4) 0.15 0.10


  1. R.K. Harris in Encyclopedia of Nuclear Magnetic Resonance, D.M. Granty and R.K. Harris, (eds.), vol. 5, John Wiley & Sons, Chichester, UK, 1996. I am grateful to Professor Robin Harris (University of Durham, UK) who provided much of the NMR data, which are copyright 1996 IUPAC, adapted from his contribution contained within this reference.
  2. J. Mason in Multinuclear NMR, Plenum Press, New York, USA, 1987. Where given, data for certain radioactive nuclei are from this reference.
  3. P. Pyykkö, Mol. Phys., 2008, 106, 1965-1974.
  4. P. Pyykkö, Mol. Phys., 2001, 99, 1617-1629.
  5. P. Pyykkö, Z. Naturforsch., 1992, 47a, 189. I am grateful to Professor Pekka Pyykkö (University of Helsinki, Finland) who provided the nuclear quadrupole moment data in this and the following two references.
  6. D.R. Lide, (ed.), CRC Handbook of Chemistry and Physics 1999-2000 : A Ready-Reference Book of Chemical and Physical Data (CRC Handbook of Chemistry and Physics, CRC Press, Boca Raton, Florida, USA, 79th edition, 1998.
  7. P. Pyykkö, personal communication, 1998, 204, 2008, 2010.

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