Isotopes of bromine

Isotopes of bromine (35Br)
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
75Br synth 96.7 min β+ 75Se
76Br synth 16.2 h β+ 76Se
77Br synth 57.04 h β+ 77Se
79Br 50.6% stable
80mBr synth 4.4205 h IT 80Br
81Br 49.4% stable
82Br synth 35.282 h β 82Kr
Standard atomic weight Ar°(Br)
  • [79.90179.907]
  • 79.904±0.003 (abridged)

Bromine (35Br) has two stable isotopes, 79Br and 81Br, and 35 known radioisotopes, the most stable of which is 77Br, with a half-life of 57.036 hours.

Like the radioactive isotopes of iodine, radioisotopes of bromine, collectively radiobromine, can be used to label biomolecules for nuclear medicine; for example, the positron emitters 75Br and 76Br can be used for positron emission tomography. Radiobromine has the advantage that organobromides are more stable than analogous organoiodides, and that it is not uptaken by the thyroid like iodine.

List of isotopes

Nuclide
Z N Isotopic mass (Da)
Half-life
Decay
mode

Daughter
isotope

Spin and
parity
Natural abundance (mole fraction)
Excitation energy Normal proportion Range of variation
68Br 35 33 67.95836(28)# ~35 ns p? 67Se 3+#
69Br 35 34 68.950338(45) <19 ns p 68Se (5/2−)
70Br 35 35 69.944792(16) 78.8(3) ms β+ 70Se 0+
β+, p? 69As
70mBr 2292.3(8) keV 2.16(5) s β+ 70Se 9+
β+, p? 69As
71Br 35 36 70.9393422(58) 21.4(6) s β+ 71Se (5/2)−
72Br 35 37 71.9365946(11) 78.6(24) s β+ 72Se 1+
72mBr 100.76(15) keV 10.6(3) s IT 72Br (3-)
β+? 72Se
73Br 35 38 72.9316734(72) 3.4(2) min β+ 73Se 1/2−
74Br 35 39 73.9299103(63) 25.4(3) min β+ 74Se (0−)
74mBr 13.58(21) keV 46(2) min β+ 74Se 4+
75Br 35 40 74.9258106(46) 96.7(13) min β+ (76%) 75Se 3/2−
EC (24%) 76Se
76Br 35 41 75.924542(10) 16.2(2) h β+ (57%) 76Se 1−
EC (43%) 76Se
76mBr 102.58(3) keV 1.31(2) s IT (>99.4%) 76Br (4)+
β+ (<0.6%) 76Se
77Br 35 42 76.9213792(30) 57.04(12) h EC (99.3%) 77Se 3/2−
β+ (0.7%) 77Se
77mBr 105.86(8) keV 4.28(10) min IT 77Br 9/2+
78Br 35 43 77.9211459(38) 6.45(4) min β+ (>99.99%) 78Se 1+
β (<0.01%) 78Kr
78mBr 180.89(13) keV 119.4(10) μs IT 78Br (4+)
79Br 35 44 78.9183376(11) Stable 3/2− 0.5065(9)
79mBr 207.61(9) keV 4.85(4) s IT 79Br 9/2+
80Br 35 45 79.9185298(11) 17.68(2) min β (91.7%) 80Kr 1+
β+ (8.3%) 80Se
80mBr 85.843(4) keV 4.4205(8) h IT 80Br 5−
81Br 35 46 80.9162882(10) Stable 3/2− 0.4935(9)
81mBr 536.20(9) keV 34.6(28) μs IT 81Br 9/2+
82Br 35 47 81.9168018(10) 35.282(7) h β 82Kr 5−
82mBr 45.9492(10) keV 6.13(5) min IT (97.6%) 82Br 2−
β (2.4%) 82Kr
83Br 35 48 82.9151753(41) 2.374(4) h β 83Kr 3/2−
83mBr 3069.2(4) keV 729(77) ns IT 83Br (19/2−)
84Br 35 49 83.916496(28) 31.76(8) min β 84Kr 2−
84m1 310(100) keV 6.0(2) min β 84Kr (6)−
84m2Br 408.2(4) keV <140 ns IT 84Br 1+
85Br 35 50 84.9156458(33) 2.90(6) min β 85Kr 3/2−
86Br 35 51 85.9188054(33) 55.1(4) s β 86Kr (1−)
87Br 35 52 86.9206740(34) 55.68(12) s β (97.40%) 87Kr 5/2−
β, n (2.60%) 86Kr
88Br 35 53 87.9240833(34) 16.34(8) s β (93.42%) 88Kr (1−)
β, n (6.58%) 87Kr
88mBr 270.17(11) keV 5.51(4) μs IT 88Br (4−)
89Br 35 54 88.9267046(35) 4.357(22) s β (86.2%) 89Kr (3/2−, 5/2−)
β, n (13.8%) 88Kr
90Br 35 55 89.9312928(36) 1.910(10) s β (74.7%) 90Kr
β, n (25.3%) 89Kr
91Br 35 56 90.9343986(38) 543(4) ms β (70.5%) 91Kr 5/2−#
β, n (29.5%) 90Kr
92Br 35 57 91.9396316(72) 314(16) ms β (66.9%) 92Kr (2−)
β, n (33.1%) 91Kr
β, 2n? 90Kr
92m1Br 662(1) keV 88(8) ns IT 92Br
92m2Br 1138(1) keV 85(10) ns IT 92Br
93Br 35 58 92.94322(46) 152(8) ms β, n (64%) 92Kr 5/2−#
β (36%) 93Kr
β, 2n? 91Kr
94Br 35 59 93.94885(22)# 70(20) ms β, n (68%) 93Kr 2−#
β (32%) 94Kr
β, 2n? 92Kr
94mBr 294.6(5) keV 530(15) ns IT 94Br
95Br 35 60 94.95293(32)# 80# ms [>300 ns] β? 95Kr 5/2−#
β, n? 94Kr
β, 2n? 93Kr
95mBr 537.9(5) keV 6.8(10) μs IT 95Br
96Br 35 61 95.95898(32)# 20# ms [>300 ns] β? 96Kr
β, n? 95Kr
β, 2n? 94Kr
96mBr 311.5(5) keV 3.0(9) μs IT 95Br
97Br 35 62 96.96350(43)# 40# ms [>300 ns] β? 97Kr 5/2−#
β, n? 96Kr
β, 2n? 95Kr
98Br 35 63 97.96989(43)# 15# ms [>400 ns] β? 98Kr
β, n? 97Kr
β, 2n? 96Kr
99Br 35 64
100Br 35 65
101Br 35 66
This table header & footer:
  1. ^ mBr – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^ Modes of decay:
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  5. ^ Bold italics symbol as daughter – Daughter product is nearly stable.
  6. ^ Bold symbol as daughter – Daughter product is stable.
  7. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  8. ^ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

Bromine-75

Bromine-75 has a half-life of 97 minutes. This isotope undergoes β+ decay rather than electron capture about 76% of the time, so it was used for diagnosis and positron emission tomography (PET) in the 1980s. However, its decay product, selenium-75, produces secondary radioactivity with a longer half-life of 120.4 days.

Bromine-76

Bromine-76 has a half-life of 16.2 hours. While its decay is more energetic than 75Br and has lower yield of positrons (about 57% of decays), bromine-76 has been preferred in PET applications since the 1980s because of its longer half-life and easier synthesis, and because its decay product, 76Se, is not radioactive.

Bromine-77

Bromine-77 is the most stable radioisotope of bromine, with a half-life of 57 hours. Although β+ decay is possible for this isotope, about 99.3% of decays are by electron capture. Despite its complex emission spectrum, featuring strong gamma-ray emissions at 239, 297, 521, and 579 keV, 77Br was used in SPECT imaging in the 1970s, but except for longer-term tracing, this is no longer considered practical due to the difficult collimator requirements and the proximity of the 521 keV line to the 511 keV annihilation radiation related to the β+ decay. However, the auger electrons emitted during decay are well-suited for radiotherapy, and it can possibly be paired with the imaging-suited 76Br (produced as an impurity in common synthesis routes) for this application.


This page was last updated at 2024-04-17 14:34 UTC. Update now. View original page.

All our content comes from Wikipedia and under the Creative Commons Attribution-ShareAlike License.


Top

If mathematical, chemical, physical and other formulas are not displayed correctly on this page, please useFirefox or Safari