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Standard atomic weight Ar°(Br) | ||||||||||||||||||||||||||||||||||||||||||||||
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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. [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]
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 | |||||||||||||||||
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%) | 76Se | ||||||||||||||||||
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 | 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− | 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 [11] | 35 | 64 | |||||||||||||||||
100Br [11] | 35 | 65 | |||||||||||||||||
101Br [12] | 35 | 66 | |||||||||||||||||
This table header & footer: |
IT: | Isomeric transition |
n: | Neutron emission |
p: | Proton emission |
Bromine-75 has a half-life of 97 minutes. [13] This isotope undergoes β+ decay 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 120.4 days. [6] [4]
Bromine-76 has a half-life of 16.2 hours. [13] While its decay is more energetic than 75Br and has 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 is the most stable radioisotope of bromine, with a half-life of 57 hours. [13] 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, [14] 77Br was used in SPECT imaging in the 1970s. [15] 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. [15] 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] [15]
Astatine (85At) has 41 known isotopes, all of which are radioactive; their mass numbers range from 188 to 229. There are also 24 known metastable excited states. The longest-lived isotope is 210At, which has a half-life of 8.1 hours; the longest-lived isotope existing in naturally occurring decay chains is 219At with a half-life of 56 seconds.
Bismuth (83Bi) has 41 known isotopes, ranging from 184Bi to 224Bi. Bismuth has no stable isotopes, but does have one very long-lived isotope; thus, the standard atomic weight can be given as 208.98040(1). Although bismuth-209 is now known to be radioactive, it has classically been considered to be a stable isotope because it has a half-life of approximately 2.01×1019 years, which is more than a billion times the age of the universe. Besides 209Bi, the most stable bismuth radioisotopes are 210mBi with a half-life of 3.04 million years, 208Bi with a half-life of 368,000 years and 207Bi, with a half-life of 32.9 years, none of which occurs in nature. All other isotopes have half-lives under 1 year, most under a day. Of naturally occurring radioisotopes, the most stable is radiogenic 210Bi with a half-life of 5.012 days. 210mBi is unusual for being a nuclear isomer with a half-life multiple orders of magnitude longer than that of the ground state.
Thallium (81Tl) has 41 isotopes with atomic masses that range from 176 to 216. 203Tl and 205Tl are the only stable isotopes and 204Tl is the most stable radioisotope with a half-life of 3.78 years. 207Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
There are seven stable isotopes of mercury (80Hg) with 202Hg being the most abundant (29.86%). The longest-lived radioisotopes are 194Hg with a half-life of 444 years, and 203Hg with a half-life of 46.612 days. Most of the remaining 40 radioisotopes have half-lives that are less than a day. 199Hg and 201Hg are the most often studied NMR-active nuclei, having spin quantum numbers of 1/2 and 3/2 respectively. All isotopes of mercury are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. These isotopes are predicted to undergo either alpha decay or double beta decay.
Naturally occurring platinum (78Pt) consists of five stable isotopes (192Pt, 194Pt, 195Pt, 196Pt, 198Pt) and one very long-lived (half-life 4.83×1011 years) radioisotope (190Pt). There are also 34 known synthetic radioisotopes, the longest-lived of which is 193Pt with a half-life of 50 years. All other isotopes have half-lives under a year, most under a day. All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope.
There are two natural isotopes of iridium (77Ir), and 37 radioisotopes, the most stable radioisotope being 192Ir with a half-life of 73.83 days, and many nuclear isomers, the most stable of which is 192m2Ir with a half-life of 241 years. All other isomers have half-lives under a year, most under a day. All isotopes of iridium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
Naturally occurring ytterbium (70Yb) is composed of seven stable isotopes: 168Yb, 170Yb–174Yb, and 176Yb, with 174Yb being the most abundant. 30 radioisotopes have been characterized, with the most stable being 169Yb with a half-life of 32.014 days, 175Yb with a half-life of 4.185 days, and 166Yb with a half-life of 56.7 hours. All of the remaining radioactive isotopes have half-lives that are less than 2 hours, and the majority of these have half-lives that are less than 20 minutes. This element also has 18 meta states, with the most stable being 169mYb.
Naturally occurring terbium (65Tb) is composed of one stable isotope, 159Tb. Thirty-seven radioisotopes have been characterized, with the most stable being 158Tb with a half-life of 180 years, 157Tb with a half-life of 71 years, and 160Tb with a half-life of 72.3 days. All of the remaining radioactive isotopes have half-lives that are less than 6.907 days, and the majority of these have half-lives that are less than 24 seconds. This element also has 27 meta states, with the most stable being 156m1Tb, 154m2Tb and 154m1Tb.
Naturally occurring cerium (58Ce) is composed of 4 stable isotopes: 136Ce, 138Ce, 140Ce, and 142Ce, with 140Ce being the most abundant and the only one theoretically stable; 136Ce, 138Ce, and 142Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being 144Ce, with a half-life of 284.893 days; 139Ce, with a half-life of 137.640 days and 141Ce, with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states.
Naturally occurring barium (56Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe).
Antimony (51Sb) occurs in two stable isotopes, 121Sb and 123Sb. There are 37 artificial radioactive isotopes, the longest-lived of which are 125Sb, with a half-life of 2.75856 years; 124Sb, with a half-life of 60.2 days; and 126Sb, with a half-life of 12.35 days. All other isotopes have half-lives less than 4 days, most less than an hour. There are also many isomers, the longest-lived of which is 120m1Sb with a half-life of 5.76 days.
Natural yttrium (39Y) is composed of a single isotope yttrium-89. The most stable radioisotopes are 88Y, which has a half-life of 106.6 days, and 91Y, with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87Y, which has a half-life of 79.8 hours, and 90Y, with 64 hours. The dominant decay mode below the stable 89Y is electron capture and the dominant mode after it is beta emission. Thirty-five unstable isotopes have been characterized.
Arsenic (33As) has 32 known isotopes and at least 10 isomers. Only one of these isotopes, 75As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is 73As with a half-life of 80 days.
Germanium (32Ge) has five naturally occurring isotopes, 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Of these, 76Ge is very slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 1021 years (130 billion times the age of the universe).
Natural gallium (31Ga) consists of a mixture of two stable isotopes: gallium-69 and gallium-71. Twenty-nine radioisotopes are known, all synthetic, with atomic masses ranging from 60 to 89; along with three nuclear isomers, 64mGa, 72mGa and 74mGa. Most of the isotopes with atomic mass numbers below 69 decay to isotopes of zinc, while most of the isotopes with masses above 71 decay to isotopes of germanium. Among them, the most commercially important radioisotopes are gallium-67 and gallium-68.
Copper (29Cu) has two stable isotopes, 63Cu and 65Cu, along with 28 radioisotopes. The most stable radioisotope is 67Cu with a half-life of 61.83 hours. Most of the others have half-lives under a minute. Unstable copper isotopes with atomic masses below 63 tend to undergo β+ decay, while isotopes with atomic masses above 65 tend to undergo β− decay. 64Cu decays by both β+ and β−.
Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-seven radioisotopes have been characterized, with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours and 44Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound 39Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being 44m2Sc.
Fermium (100Fm) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered was 255Fm in 1952. 250Fm was independently synthesized shortly after the discovery of 255Fm. There are 20 known radioisotopes ranging in atomic mass from 241Fm to 260Fm, and 4 nuclear isomers, 247mFm, 250mFm, 251mFm, and 253mFm. The longest-lived isotope is 257Fm with a half-life of 100.5 days, and the longest-lived isomer is 247mFm with a half-life of 5.1 seconds.
Einsteinium (99Es) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be discovered was 253Es in 1952. There are 18 known radioisotopes from 240Es to 257Es, and 4 nuclear isomers. The longest-lived isotope is 252Es with a half-life of 471.7 days, or around 1.293 years.
Mendelevium (101Md) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 256Md in 1955. There are 17 known radioisotopes, ranging in atomic mass from 244Md to 260Md, and 5 isomers. The longest-lived isotope is 258Md with a half-life of 51.3 days, and the longest-lived isomer is 258mMd with a half-life of 57 minutes.