# Isotopes of bromine

Bromine ($_{35}$Br) has two stable isotopes, $^{79}$Br and $^{81}$Br, and 35 known radioisotopes, the most stable of which is $^{77}$Br, 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 $^{75}$Br and $^{76}$Br 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) | Natural abundance (mole fraction) |
| Nuclide | Excitation energy | Excitation energy | Excitation energy | Half-life | Decay mode | Daughter isotope | Spin and parity | Normal proportion | Range of variation |
| $^{68}$Br | 35 | 33 | 67.95836(28)# | ~35 ns | p? | $^{67}$Se | 3+# | | |
| $^{69}$Br | 35 | 34 | 68.950338(45) | <19 ns | p | $^{68}$Se | (5/2−) | | |
| $^{70}$Br | 35 | 35 | 69.944792(16) | 78.8(3) ms | β$^+$ | $^{70}$Se | 0+ | | |
| $^{70}$Br | 35 | 35 | 69.944792(16) | 78.8(3) ms | β$^+$, p? | $^{69}$As | 0+ | | |
| $^{70m}$Br | 2292.3(8) keV | 2292.3(8) keV | 2292.3(8) keV | 2.16(5) s | β$^+$ | $^{70}$Se | 9+ | | |
| $^{70m}$Br | 2292.3(8) keV | 2292.3(8) keV | 2292.3(8) keV | 2.16(5) s | β$^+$, p? | $^{69}$As | 9+ | | |
| $^{71}$Br | 35 | 36 | 70.9393422(58) | 21.4(6) s | β$^+$ | $^{71}$Se | (5/2)− | | |
| $^{72}$Br | 35 | 37 | 71.9365946(11) | 78.6(24) s | β$^+$ | $^{72}$Se | 1+ | | |
| $^{72m}$Br | 100.76(15) keV | 100.76(15) keV | 100.76(15) keV | 10.6(3) s | IT | $^{72}$Br | (3−) | | |
| $^{72m}$Br | 100.76(15) keV | 100.76(15) keV | 100.76(15) keV | 10.6(3) s | β$^+$? | $^{72}$Se | (3−) | | |
| $^{73}$Br | 35 | 38 | 72.9316734(72) | 3.4(2) min | β$^+$ | $^{73}$Se | 1/2− | | |
| $^{74}$Br | 35 | 39 | 73.9299103(63) | 25.4(3) min | β$^+$ | $^{74}$Se | (0−) | | |
| $^{74m}$Br | 13.58(21) keV | 13.58(21) keV | 13.58(21) keV | 46(2) min | β$^+$ | $^{74}$Se | 4+ | | |
| $^{75}$Br | 35 | 40 | 74.9258106(46) | 96.7(13) min | β$^+$ (76%) | $^{75}$Se | 3/2− | | |
| $^{75}$Br | 35 | 40 | 74.9258106(46) | 96.7(13) min | EC (24%) | $^{75}$Se | 3/2− | | |
| $^{76}$Br | 35 | 41 | 75.924542(10) | 16.2(2) h | β$^+$ (57%) | $^{76}$Se | 1− | | |
| $^{76}$Br | 35 | 41 | 75.924542(10) | 16.2(2) h | EC (43%) | $^{76}$Se | 1− | | |
| $^{76m}$Br | 102.58(3) keV | 102.58(3) keV | 102.58(3) keV | 1.31(2) s | IT (>99.4%) | $^{76}$Br | (4)+ | | |
| $^{76m}$Br | 102.58(3) keV | 102.58(3) keV | 102.58(3) keV | 1.31(2) s | β$^+$ (<0.6%) | $^{76}$Se | (4)+ | | |
| $^{77}$Br | 35 | 42 | 76.9213792(30) | 57.04(12) h | EC (99.3%) | $^{77}$Se | 3/2− | | |
| $^{77}$Br | 35 | 42 | 76.9213792(30) | 57.04(12) h | β$^+$ (0.7%) | $^{77}$Se | 3/2− | | |
| $^{77m}$Br | 105.86(8) keV | 105.86(8) keV | 105.86(8) keV | 4.28(10) min | IT | $^{77}$Br | 9/2+ | | |
| $^{78}$Br | 35 | 43 | 77.9211459(38) | 6.45(4) min | β$^+$ (>99.99%) | $^{78}$Se | 1+ | | |
| $^{78}$Br | 35 | 43 | 77.9211459(38) | 6.45(4) min | β$^−$ (<0.01%) | $^{78}$Kr | 1+ | | |
| $^{78m}$Br | 180.89(13) keV | 180.89(13) keV | 180.89(13) keV | 119.4(10) μs | IT | $^{78}$Br | (4+) | | |
| $^{79}$Br | 35 | 44 | 78.9183376(11) | Stable | Stable | Stable | 3/2− | 0.5065(9) | |
| $^{79m}$Br | 207.61(9) keV | 207.61(9) keV | 207.61(9) keV | 4.85(4) s | IT | $^{79}$Br | 9/2+ | | |
| $^{80}$Br | 35 | 45 | 79.9185298(11) | 17.68(2) min | β$^−$ (91.7%) | $^{80}$Kr | 1+ | | |
| $^{80}$Br | 35 | 45 | 79.9185298(11) | 17.68(2) min | β$^+$ (8.3%) | $^{80}$Se | 1+ | | |
| $^{80m}$Br | 85.843(4) keV | 85.843(4) keV | 85.843(4) keV | 4.4205(8) h | IT | $^{80}$Br | 5− | | |
| $^{81}$Br | 35 | 46 | 80.9162882(10) | Stable | Stable | Stable | 3/2− | 0.4935(9) | |
| $^{81m}$Br | 536.20(9) keV | 536.20(9) keV | 536.20(9) keV | 34.6(28) μs | IT | $^{81}$Br | 9/2+ | | |
| $^{82}$Br | 35 | 47 | 81.9168018(10) | 35.282(7) h | β$^−$ | $^{82}$Kr | 5− | | |
| $^{82m}$Br | 45.9492(10) keV | 45.9492(10) keV | 45.9492(10) keV | 6.13(5) min | IT (97.6%) | $^{82}$Br | 2− | | |
| $^{82m}$Br | 45.9492(10) keV | 45.9492(10) keV | 45.9492(10) keV | 6.13(5) min | β$^−$ (2.4%) | $^{82}$Kr | 2− | | |
| $^{83}$Br | 35 | 48 | 82.9151753(41) | 2.374(4) h | β$^−$ | $^{83}$Kr | 3/2− | | |
| $^{83m}$Br | 3069.2(4) keV | 3069.2(4) keV | 3069.2(4) keV | 729(77) ns | IT | $^{83}$Br | (19/2−) | | |
| $^{84}$Br | 35 | 49 | 83.9165136(17) | 31.76(8) min | β$^−$ | $^{84}$Kr | 2− | | |
| $^{84m1}$Br | 193.6(15) keV | 193.6(15) keV | 193.6(15) keV | 6.0(2) min | β$^−$ | $^{84}$Kr | (6)− | | |
| $^{84m2}$Br | 408.2(4) keV | 408.2(4) keV | 408.2(4) keV | <140 ns | IT | $^{84}$Br | 1+ | | |
| $^{85}$Br | 35 | 50 | 84.9156458(33) | 2.90(6) min | β$^−$ | $^{85}$Kr | 3/2− | | |
| $^{86}$Br | 35 | 51 | 85.9188054(33) | 55.1(4) s | β$^−$ | $^{86}$Kr | (1−) | | |
| $^{87}$Br | 35 | 52 | 86.9206740(34) | 55.68(12) s | β$^−$ (97.40%) | $^{87}$Kr | 5/2− | | |
| $^{87}$Br | 35 | 52 | 86.9206740(34) | 55.68(12) s | β$^−$, n (2.60%) | $^{86}$Kr | 5/2− | | |
| $^{88}$Br | 35 | 53 | 87.9240833(34) | 16.34(8) s | β$^−$ (93.42%) | $^{88}$Kr | (1−) | | |
| $^{88}$Br | 35 | 53 | 87.9240833(34) | 16.34(8) s | β$^−$, n (6.58%) | $^{87}$Kr | (1−) | | |
| $^{88m}$Br | 270.17(11) keV | 270.17(11) keV | 270.17(11) keV | 5.51(4) μs | IT | $^{88}$Br | (4−) | | |
| $^{89}$Br | 35 | 54 | 88.9267046(35) | 4.357(22) s | β$^−$ (86.2%) | $^{89}$Kr | (3/2−, 5/2−) | | |
| $^{89}$Br | 35 | 54 | 88.9267046(35) | 4.357(22) s | β$^−$, n (13.8%) | $^{88}$Kr | (3/2−, 5/2−) | | |
| $^{90}$Br | 35 | 55 | 89.9312928(36) | 1.910(10) s | β$^−$ (74.7%) | $^{90}$Kr | | | |
| $^{90}$Br | 35 | 55 | 89.9312928(36) | 1.910(10) s | β$^−$, n (25.3%) | $^{89}$Kr | | | |
| $^{91}$Br | 35 | 56 | 90.9343986(38) | 543(4) ms | β$^−$ (70.5%) | $^{91}$Kr | 5/2−# | | |
| $^{91}$Br | 35 | 56 | 90.9343986(38) | 543(4) ms | β$^−$, n (29.5%) | $^{90}$Kr | 5/2−# | | |
| $^{92}$Br | 35 | 57 | 91.9396316(72) | 314(16) ms | β$^−$ (66.9%) | $^{92}$Kr | (2−) | | |
| $^{92}$Br | 35 | 57 | 91.9396316(72) | 314(16) ms | β$^−$, n (33.1%) | $^{91}$Kr | (2−) | | |
| $^{92}$Br | 35 | 57 | 91.9396316(72) | 314(16) ms | β$^−$, 2n? | $^{90}$Kr | (2−) | | |
| $^{92m1}$Br | 662(1) keV | 662(1) keV | 662(1) keV | 88(8) ns | IT | $^{92}$Br | | | |
| $^{92m2}$Br | 1138(1) keV | 1138(1) keV | 1138(1) keV | 85(10) ns | IT | $^{92}$Br | | | |
| $^{93}$Br | 35 | 58 | 92.94322(46) | 152(8) ms | β$^−$, n (64%) | $^{92}$Kr | 5/2−# | | |
| $^{93}$Br | 35 | 58 | 92.94322(46) | 152(8) ms | β$^−$ (36%) | $^{93}$Kr | 5/2−# | | |
| $^{93}$Br | 35 | 58 | 92.94322(46) | 152(8) ms | β$^−$, 2n? | $^{91}$Kr | 5/2−# | | |
| $^{94}$Br | 35 | 59 | 93.94885(22)# | 70(20) ms | β$^−$, n (68%) | $^{93}$Kr | 2−# | | |
| $^{94}$Br | 35 | 59 | 93.94885(22)# | 70(20) ms | β$^−$ (32%) | $^{94}$Kr | 2−# | | |
| $^{94}$Br | 35 | 59 | 93.94885(22)# | 70(20) ms | β$^−$, 2n? | $^{92}$Kr | 2−# | | |
| $^{94m}$Br | 294.6(5) keV | 294.6(5) keV | 294.6(5) keV | 530(15) ns | IT | $^{94}$Br | | | |
| $^{95}$Br | 35 | 60 | 94.95293(32)# | 80# ms [>300 ns] | β$^−$? | $^{95}$Kr | 5/2−# | | |
| $^{95}$Br | 35 | 60 | 94.95293(32)# | 80# ms [>300 ns] | β$^−$, n? | $^{94}$Kr | 5/2−# | | |
| $^{95}$Br | 35 | 60 | 94.95293(32)# | 80# ms [>300 ns] | β$^−$, 2n? | $^{93}$Kr | 5/2−# | | |
| $^{95m}$Br | 537.9(5) keV | 537.9(5) keV | 537.9(5) keV | 6.8(10) μs | IT | $^{95}$Br | | | |
| $^{96}$Br | 35 | 61 | 95.95898(32)# | 20# ms [>300 ns] | β$^−$? | $^{96}$Kr | | | |
| $^{96}$Br | 35 | 61 | 95.95898(32)# | 20# ms [>300 ns] | β$^−$, n? | $^{95}$Kr | | | |
| $^{96}$Br | 35 | 61 | 95.95898(32)# | 20# ms [>300 ns] | β$^−$, 2n? | $^{94}$Kr | | | |
| $^{96m}$Br | 311.5(5) keV | 311.5(5) keV | 311.5(5) keV | 3.0(9) μs | IT | $^{95}$Br | | | |
| $^{97}$Br | 35 | 62 | 96.96350(43)# | 40# ms [>300 ns] | β$^−$? | $^{97}$Kr | 5/2−# | | |
| $^{97}$Br | 35 | 62 | 96.96350(43)# | 40# ms [>300 ns] | β$^−$, n? | $^{96}$Kr | 5/2−# | | |
| $^{97}$Br | 35 | 62 | 96.96350(43)# | 40# ms [>300 ns] | β$^−$, 2n? | $^{95}$Kr | 5/2−# | | |
| $^{98}$Br | 35 | 63 | 97.96989(43)# | 15# ms [>400 ns] | β$^−$? | $^{98}$Kr | | | |
| $^{98}$Br | 35 | 63 | 97.96989(43)# | 15# ms [>400 ns] | β$^−$, n? | $^{97}$Kr | | | |
| $^{98}$Br | 35 | 63 | 97.96989(43)# | 15# ms [>400 ns] | β$^−$, 2n? | $^{96}$Kr | | | |
| $^{99}$Br | 35 | 64 | | | | | | | |
| $^{100}$Br | 35 | 65 | | | | | | | |
| $^{101}$Br | 35 | 66 | | | | | | | |
| This table header & footer: view ||||||||||
* ↑ $^m$Br – Excited nuclear isomer.
* ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
* ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
* ↑ Modes of decay: IT:Isomeric transition n:Neutron emission p:Proton emission
* ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
* ↑ Bold symbol as daughter – Daughter product is stable.
* ↑ ( ) spin value – Indicates spin with weak assignment arguments.
* ↑ # – 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 $^{75}$Br 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, $^{76}$Se, 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, $^{77}$Br was used in SPECT imaging in the 1970s. However, 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. The Auger electrons emitted during decay are nevertheless well-suited for radiotherapy, and $^{77}$Br can possibly be paired with the imaging-suited $^{76}$Br (produced as an impurity in common synthesis routes) for this application.