Physics:Isotopes of boron

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Short description: Nuclides with atomic number of 5 but with different mass numbers
Main isotopes of Chemistry:boron (5B)
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, standard(B)
  • [10.806, 10.821][3]
  • Conventional: 10.81
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Boron (5B) naturally occurs as isotopes 10B and 11B, the latter of which makes up about 80% of natural boron. There are 13 radioisotopes that have been discovered, with mass numbers from 7 to 21, all with short half-lives, the longest being that of 8B, with a half-life of only 771.9(9) ms and 12B with a half-life of 20.20(2) ms. All other isotopes have half-lives shorter than 17.35 ms. 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.

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

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (u)
[n 2][n 3] 		Half-life

[resonance width] 		Decay
mode
[n 4] 		Daughter
isotope
[n 5] 		Spin and
parity
[n 6][n 7] 		Physics:Natural abundance (mole fraction)
Excitation energy Normal proportion Range of variation
6B?[n 8] 5  1 6.050800(2150) p-unstable 2p? 6Li? 2−#
7B 5  2 7.029712(27) 570(14) ys
[801(20) keV] 		p 6Be[n 9] (3/2−)
8B[n 10][n 11] 5  3 8.0246073(11) 771.9(9) ms β+α 4He 2+
8mB 10624(8) keV 0+
9B 5  4 9.0133296(10) 800(300) zs p 8Be[n 12] 3/2−
10B[n 13] 5  5 10.012936862(16) Stable 3+ [0.189, 0.204][4]
11B 5  6 11.009305167(13) Stable 3/2− [0.796, 0.811][4]
11mB 12560(9) keV 1/2+, (3/2+)
12B 5  7 12.0143526(14) 20.20(2) ms β− (99.40(2)%) 12C 1+
β−α (0.60(2)%) 8Be[n 14]
13B 5  8 13.0177800(11) 17.16(18) ms β− (99.734(36)%) 13C 3/2−
β−n (0.266(36)%) 12C
14B 5  9 14.025404(23) 12.36(29) ms β− (93.96(23)%) 14C 2−
β−n (6.04(23)%) 13C
β−2n ?[n 15] 12C ?
14mB 17065(29) keV 4.15(1.90) zs IT ?[n 15] 0+
15B 5 10 15.031087(23) 10.18(35) ms β−n (98.7(1.0)%) 14C 3/2−
β− (< 1.3%) 15C
β−2n (< 1.5%) 13C
16B 5 11 16.039841(26) > 4.6 zs n ?[n 15] 15B ? 0−
17B[n 16] 5 12 17.04693(22) 5.08(5) ms β−n (63(1)%) 16C (3/2−)
β− (21.1(2.4)%) 17C
β−2n (12(2)%) 15C
β−3n (3.5(7)%) 14C
β−4n (0.4(3)%) 13C
18B 5 13 18.05560(22) < 26 ns n 17B (2−)
19B[n 16] 5 14 19.06417(56) 2.92(13) ms β−n (71(9)%) 18C (3/2−)
β−2n (17(5)%) 17C
β−3n (< 9.1%) 16C
β− (> 2.9%) 19C
20B[5] 5 15 20.07451(59) > 912.4 ys n 19B (1−, 2−)
21B[5] 5 16 21.08415(60) > 760 ys 2n 19B (3/2−)
  1. ↑ mB – Excited nuclear isomer.
  2. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ↑ Modes of decay:
    n: Neutron emission
    p: Proton emission
  5. ↑ Bold symbol as daughter – Daughter product is stable.
  6. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  7. ↑ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  8. ↑ This isotope has not yet been observed; given data is inferred or estimated from periodic trends.
  9. ↑ Subsequently decays by double proton emission to 4He for a net reaction of 7B → 4He + 3 1H
  10. ↑ Has 1 halo proton
  11. ↑ Intermediate product of a branch of proton-proton chain in stellar nucleosynthesis as part of the process converting hydrogen to helium
  12. ↑ Immediately decays into two α particles, for a net reaction of 9B → 2 4He + 1H
  13. ↑ One of the few stable odd-odd nuclei
  14. ↑ Immediately decays into two α particles, for a net reaction of 12B → 3 4He +  e−
  15. ↑ 15.0 15.1 15.2 Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
  16. ↑ 16.0 16.1 Has 2 halo neutrons

Boron-8

Boron-8 is an isotope of boron that undergoes β+ decay to beryllium-8 with a half-life of 771.9(9) ms. It is the strongest candiate for a halo nucleus with a loosely-bound proton, in contrast to neutron halo nuclei such as lithium-11.[6]

Although neutrinos from boron-8 beta decays within the Sun make up only about 80 ppm of the total solar neutrino flux, they have a higher energy centered around 10 MeV,[7] and are an important background to dark matter direct detection experiments.[8] They are the first component of the neutrino floor that dark matter direct detection experiments are expected to eventually encounter.

Applications

Boron-10

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

References

  1. ↑ 1.0 1.1 "Atomic Weights and Isotopic Compositions for All Elements". National Institute of Standards and Technology. http://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl. 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, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry 88 (3): 265–91. doi:10.1515/pac-2015-0305. 
  4. ↑ 4.0 4.1 "Atomic Weight of Boron". https://ciaaw.org/boron.htm. 
  5. ↑ 5.0 5.1 Leblond, S. (2018). "First observation of 20B and 21B". Physical Review Letters 121 (26): 262502–1–262502–6. doi:10.1103/PhysRevLett.121.262502. PMID 30636115. 
  6. ↑ Maaß, Bernhard; Müller, Peter; Nörtershäuser, Wilfried; Clark, Jason; Gorges, Christian; Kaufmann, Simon; König, Kristian; Krämer, Jörg et al. (November 2017). "Towards laser spectroscopy of the proton-halo candidate boron-8". Hyperfine Interactions 238 (1): 25. doi:10.1007/s10751-017-1399-5. Bibcode: 2017HyInt.238...25M. 
  7. ↑ Bellerive, A. (2004). "Review of solar neutrino experiments". International Journal of Modern Physics A 19 (8): 1167–1179. doi:10.1142/S0217751X04019093. Bibcode: 2004IJMPA..19.1167B. 
  8. ↑ 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 (5): 118. doi:10.1007/JHEP05(2016)118. Bibcode: 2016JHEP...05..118C. 


https://borates.today/isotopes-a-comprehensive-guide/#:~:text=Boron%20isotope%20elements%20with%20masses,11%20mostly%20decay%20into%20carbon.



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