Isotopes of bromine

Bromine (₃₅Br) has two stable isotopes, ⁷⁹Br and ⁸¹Br, with nearly equal natural abundance, and 32 known artificial radioisotopes from ⁶⁸Br to ¹⁰¹Br, the most stable of which is ⁷⁷Br, with a half-life of 57.04 hours. This is followed by ⁸²Br at 35.282 hours and ⁷⁶Br at 16.2 hours; the most stable isomer is ^80mBr with the half-life of 4.4205 hours.

Isotopes of bromine (₃₅Br)

Main isotopes[1] Decay Isotope abun­dance half-life (t1/2) mode pro­duct 75Br synth 97 min β+ 75Se 76Br synth 16.2 h β+ 76Se 77Br synth 57.04 h β+ 77Se 79Br 50.6% stable 80Br synth 17.68 min β− 80Kr β+ 80Se 80mBr synth 4.4205 h IT 80Br 81Br 49.4% stable 82Br synth 35.282 h β− 82Kr
Standard atomic weight Ar°(Br)
	[79.901, 79.907][2] 79.904±0.003 (abridged)[3]
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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.^[4][5] Radiobromine has the advantage that organobromides are more stable than analogous organoiodides, and that it is not uptaken by the thyroid like iodine.^[6]

List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da)[7] [n 2][n 3]	Half-life[1]	Decay mode[1] [n 4]	Daughter isotope [n 5][n 6]	Spin and parity[1] [n 7][n 8]	Natural abundance (mole fraction)
	Excitation energy							Normal proportion[1]	Range of variation
67Br	35	32
68Br[8]	35	33	67.95836(28)#	~35 ns	p?	67Se	3+#
69Br	35	34	68.950338(45)	<19 ns[8]	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%)[6]	75Se	3/2−
					EC (24%)	75Se
76Br	35	41	75.924542(10)	16.2(2) h	β+ (57%)[6]	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%)[9]	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[n 9]	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	83.9165136(17)[10]	31.76(8) min	β−	84Kr	2−
84m1Br	193.6(15) keV[10]			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−	85m1Kr[11]	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	96Br
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[12]	35	64
100Br[12]	35	65
101Br[13]	35	66
This table header & footer: view

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).
9. Fission product

Bromine-75

Bromine-75 has a half-life of 97 minutes.^[14] This isotope undergoes positron emission rather than electron capture about 76% of the time,^[6] so it was used for diagnosis and positron emission tomography (PET) in the 1980s.^[4] However, its decay product, selenium-75, produces secondary radioactivity with a longer half-life of around 120 days.^[6][4]

Bromine-76

Bromine-76 has a half-life of 16.2 hours.^[14] While its decay is more energetic than ⁷⁵Br and has a lower yield of positrons, about 57% of decays,^[6] 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.^[5]

Bromine-77

Bromine-77 is the most stable radioisotope of bromine, with a half-life of 57.04 hours.^[14] Although β⁺ decay is possible for this isotope, about 99.3% of decays are by electron capture.^[9] Despite its complex emission spectrum, featuring strong gamma-ray emissions at 239, 297, 521, and 579 keV,^{[15] 77}Br was used in SPECT imaging in the 1970s.^[16] However, except for longer-term tracing,^[6] 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.^[16] The Auger electrons emitted during decay are nevertheless well-suited for radiotherapy, and ⁷⁷Br can possibly be paired with the imaging-suited ⁷⁶Br (produced as an impurity in common synthesis routes) for this application.^[4][16]

See also

Daughter products other than bromine

• Isotopes of krypton
• Isotopes of selenium
• Isotopes of arsenic