Isotopes of boron

Main isotopes of boron
Iso­tope Decay
abun­dance half-life (t1/2) mode pro­duct
10B 20% stable[1]
11B 80% stable[1]
10B content may be as low as 19.1% and as high as 20.3% in natural samples. 11B is the remainder in such cases.[2]
Standard atomic weight (Ar)
  • [10.806, 10.821][3]
  • Conventional: 10.81

Boron (5B) naturally occurs as 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.

12B has molecular form with an icosahedral structure.

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

List of isotopes

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life decay mode(s)[4] 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]
(32−)
8B[n 2] 5 3 8.0246072(11) 770(3) ms β+, α 2 4
He
2+
9B 5 4 9.0133288(11) 800(300)×10−21 s
[0.54(21) keV]
p, α 8
Be
[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%) 12
C
1+
β, α (1.6%) 8
Be
[n 4]
13B 5 8 13.0177802(12) 17.33(17) ms β (99.72%) 13
C
32
β, n (0.279%) 12
C
14B 5 9 14.025404(23) 12.5(5) ms β (93.96%) 14
C
2−
β, n (6.04%) 13
C
15B 5 10 15.031103(24) 9.87(7) ms β, n (93.6%) 14
C
32
β (6.0%) 15
C
β, 2n (0.40%) 13
C
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
(32−)
β (22.1%) 17
C
β, 2n (11.0%) 15
C
β, 3n (3.5%) 14
C
β, 4n (0.40%) 13
C
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
(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. 1 2 "Atomic Weights and Isotopic Compositions for All Elements". National Institute of Standards and Technology. Retrieved 2008-09-21.
  2. Szegedi, S.; Váradi, M.; Buczkó, Cs. M.; Várnagy, M.; Sztaricskai, T. (1990). "Determination of boron in glass by neutron transmission method". Journal of Radioanalytical and Nuclear Chemistry Letters. 146 (3): 177. doi:10.1007/BF02165219.
  3. Meija, J.; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure Appl. Chem. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  4. "Universal Nuclide Chart". nucleonica. (Registration required (help)).
  5. "2.5.7. Standard and expanded uncertainties". Engineering Statistics Handbook. Retrieved 2010-09-16.
  6. Cerdeno, David G.; Fairbairn, Malcolm; Jubb, Thomas; Machado, Pedro; Vincent, Aaron C.; Boehm, Celine (2016). "Physics from solar neutrinos in dark matter direct detection experiments". JHEP. 2016 (05): 118. doi:10.1007/JHEP05(2016)118. Retrieved 31 July 2017.

General references

Isotopes of beryllium Isotopes of boron Isotopes of carbon
Table of nuclides
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.