Isotopes of boron

Boron (B) naturally occurs isotopes, 10B and 11B, the latter of which makes up about 80% of natural boron. There are 14 radioisotopes that 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 milliseconds (ms) and 12B with a half-life of 20.2 ms. All other isotopes have half-lives shorter than 17.35 ms, 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.

Relative atomic mass: 10.811(7)

A chart showing the abundances of the naturally-occurring isotopes of boron.

Table

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 6Be[n 1] (32−)
8B[n 2] 5 3 8.0246072(11) 770(3) ms β+, α 2 4He 2+
9B 5 4 9.0133288(11) 800(300)×10−21 s
[0.54(21) keV]
p 8Be[n 3] 32
10B 5 5 10.0129370(4) Stable 3+ 19.9(7) 18.929–20.386
11B 5 6 11.0093054(4) Stable 32 80.1(7) 79.614–81.071
12B 5 7 12.0143521(15) 20.20(2) ms β (98.4%) 12C 1+
β, α (1.6%) 8Be[n 4]
13B 5 8 13.0177802(12) 17.33(17) ms β (99.72%) 13C 32
β, n (0.279%) 12C
14B 5 9 14.025404(23) 12.5(5) ms β (93.96%) 14C 2−
β, n (6.04%) 13C
15B 5 10 15.031103(24) 9.87(7) ms β, n (93.6%) 14C 32
β (6.0%) 15C
β, 2n (0.40%) 13C
16B 5 11 16.03981(6) <190×10−12 s
[<0.1 MeV]
n 15B 0−
17B[n 5] 5 12 17.04699(18) 5.08(5) ms β, n (63.0%) 16C (32−)
β (22.1%) 17C
β, 2n (11.0%) 15C
β, 3n (3.5%) 14C
β, 4n (0.40%) 13C
18B 5 13 18.05617(86)# <26 ns n 17B (4−)#
19B[n 5] 5 14 19.06373(43)# 2.92(13) ms β 19C (32−)#
  1. Subsequently decays by double proton emission to 4He for a net reaction of 7B → 4He + 31H
  2. Has 1 halo proton
  3. immediately decays into two α particles, for a net reaction of 9B → 24He + 1H
  4. Immediately decays into two α particles, for a net reaction of 12B → 34He + e
  5. 1 2 Has 2 halo neutrons

Notes

Applications

Boron-10

Boron-10 is used in boron neutron capture therapy (BNCT) as an experimental treatment of some brain cancers.

References

Notes

  1. "Universal Nuclide Chart". nucleonica. (registration required (help)).
  2. "2.5.7. Standard and expanded uncertainties". Engineering Statistics Handbook. Retrieved 2010-09-16.

General references

Isotopes of beryllium Isotopes of boron Isotopes of carbon
Table of nuclides
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