| ||||||||||||||||||||||||||||||||||||||||||||||
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 | 83.916496(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 [10] | 35 | 64 | |||||||||||||||||
100Br [10] | 35 | 65 | |||||||||||||||||
101Br [11] | 35 | 66 | |||||||||||||||||
This table header & footer: |
IT: | Isomeric transition |
n: | Neutron emission |
p: | Proton emission |
Bromine-75 has a half-life of 97 minutes. [12] 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. [12] 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. [12] 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, [13] 77Br was used in SPECT imaging in the 1970s, [14] but 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. [14] 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. [4] [14]
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 neodymium (60Nd) is composed of 5 stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant (27.2% natural abundance), and 2 long-lived radioisotopes, 144Nd and 150Nd. In all, 33 radioisotopes of neodymium have been characterized up to now, with the most stable being naturally occurring isotopes 144Nd (alpha decay, a half-life (t1/2) of 2.29×1015 years) and 150Nd (double beta decay, t1/2 of 7×1018 years), and for practical purposes they can be considered to be stable as well. All of the remaining radioactive isotopes have half-lives that are less than 12 days, and the majority of these have half-lives that are less than 70 seconds; the most stable artificial isotope is 147Nd with a half-life of 10.98 days. This element also has 13 known meta states with the most stable being 139mNd (t1/2 5.5 hours), 135mNd (t1/2 5.5 minutes) and 133m1Nd (t1/2 ~70 seconds).
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).
Tin (50Sn) is the element with the greatest number of stable isotopes. This is probably related to the fact that 50 is a "magic number" of protons. In addition, twenty-nine unstable tin isotopes are known, including tin-100 (100Sn) and tin-132 (132Sn), which are both "doubly magic". The longest-lived tin radioisotope is tin-126 (126Sn), with a half-life of 230,000 years. The other 28 radioisotopes have half-lives of less than a year.
Naturally occurring rhodium (45Rh) is composed of only one stable isotope, 103Rh. The most stable radioisotopes are 101Rh with a half-life of 3.3 years, 102Rh with a half-life of 207 days, and 99Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized with atomic weights ranging from 88.949 u (89Rh) to 121.943 u (122Rh). Most of these have half-lives that are less than an hour except 100Rh and 105Rh. There are also numerous meta states with the most stable being 102mRh (0.141 MeV) with a half-life of about 3.7 years and 101mRh (0.157 MeV) with a half-life of 4.34 days.
Naturally occurring zirconium (40Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (96Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×1019 years; it can also undergo single beta decay, which is not yet observed, but the theoretically predicted value of t1/2 is 2.4×1020 years. The second most stable radioisotope is 93Zr, which has a half-life of 1.53 million years. Thirty other radioisotopes have been observed. All have half-lives less than a day except for 95Zr (64.02 days), 88Zr (83.4 days), and 89Zr (78.41 hours). The primary decay mode is electron capture for isotopes lighter than 92Zr, and the primary mode for heavier isotopes is beta decay.
The alkaline earth metal strontium (38Sr) has four stable, naturally occurring isotopes: 84Sr (0.56%), 86Sr (9.86%), 87Sr (7.0%) and 88Sr (82.58%). Its standard atomic weight is 87.62(1).
Rubidium (37Rb) has 36 isotopes, with naturally occurring rubidium being composed of just two isotopes; 85Rb (72.2%) and the radioactive 87Rb (27.8%).
There are 34 known isotopes of krypton (36Kr) with atomic mass numbers from 69 through 102. Naturally occurring krypton is made of five stable isotopes and one which is slightly radioactive with an extremely long half-life, plus traces of radioisotopes that are produced by cosmic rays in the atmosphere.
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 56 to 86; 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 cobalt (27Co) consists of a single stable isotope, 59Co. Twenty-eight radioisotopes have been characterized; the most stable are 60Co with a half-life of 5.2714 years, 57Co, 56Co, and 58Co. All other isotopes have half-lives of less than 18 hours and most of these have half-lives of less than 1 second. This element also has 11 meta states, all of which have half-lives of less than 15 minutes.
Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-five 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.