Boron (B) naturally occurs in two isotopes, 10B and 11B, the later of which makes up about 80% of natural boron. 14 radioisotopes have been discovered, with mass numbers from 6 to 21, all with short half-lives, the longest being that of 8B, with a half-life of only 770 ms and 12B with a half-life of 20.2 milliseconds. All other isotopes have half-lives shorter than 17.35 milliseconds, with the least stable isotope being 7B, with a half-life of 150 yoctoseconds (ys). Those isotopes with mass below 10 decay into helium (via short-lived isotopes of beryllium for 7B and 9B) while those with mass above 11 mostly become carbon.
Standard atomic mass: 10.811(7) u
Contents |
nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | decay mode(s)[1] | daughter isotope(s) |
nuclear spin |
representative isotopic composition (mole percent) |
range of natural variation (mole percent) |
---|---|---|---|---|---|---|---|---|---|
6B | 5 | 1 | 6.04681(75)# | ||||||
7B | 5 | 2 | 7.02992(8) | 350(50)×10−24 s [1.4(2) MeV] |
p | 6 Be[n 1] |
(3⁄2−) | ||
8B[n 2] | 5 | 3 | 8.0246072(11) | 770(3) ms | β+, fission | 2 4 He |
2+ | ||
9B | 5 | 4 | 9.0133288(11) | 800(300)×10−21 s [0.54(21) keV] |
p | 8 Be[n 3] |
3⁄2− | ||
10B | 5 | 5 | 10.0129370(4) | Stable | 3+ | 19.9(7) | 18.929 – 20.386 | ||
11B | 5 | 6 | 11.0093054(4) | Stable | 3⁄2− | 80.1(7) | 79.614–81.071 | ||
12B | 5 | 7 | 12.0143521(15) | 20.20(2) ms | β− (98.4%) | 12 C |
1+ | ||
β−, α (1.6%) | 8 Be[n 4] |
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13B | 5 | 8 | 13.0177802(12) | 17.33(17) ms | β− (99.72%) | 13 C |
3⁄2− | ||
β−, n (0.279%) | 12 C |
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14B | 5 | 9 | 14.025404(23) | 12.5(5) ms | β− (93.96%) | 14 C |
2− | ||
β−, n (6.04%) | 13 C |
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15B | 5 | 10 | 15.031103(24) | 9.87(7) ms | β−, n (93.6%) | 14 C |
3⁄2− | ||
β− (6.0%) | 15 C |
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β−, 2n (0.40%) | 13 C |
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16B | 5 | 11 | 16.03981(6) | <190×10−12 s [<0.1 MeV] |
n | 15 B |
0− | ||
17B[n 5] | 5 | 12 | 17.04699(18) | 5.08(5) ms | β−, n (63.0%) | 16 C |
(3⁄2−) | ||
β− (22.1%) | 17 C |
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β−, 2n (11.0%) | 15 C |
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β−, 3n (3.5%) | 14 C |
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β−, 4n (0.40%) | 13 C |
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18B | 5 | 13 | 18.05617(86)# | <26 ns | n | 17 B |
(4−)# | ||
19B[n 5] | 5 | 14 | 19.06373(43)# | 2.92(13) ms | β− | 19 C |
(3⁄2−)# |
Isotopes of beryllium | Isotopes of boron | Isotopes of carbon |
Index to isotope pages · Table of nuclides |