Isotopes of boron explained

Boron (₅B) naturally occurs as isotopes and, 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, with a half-life of only and with a half-life of . All other isotopes have half-lives shorter than . Those isotopes with mass below 10 decay into helium (via short-lived isotopes of beryllium for and) while those with mass above 11 mostly become carbon.

List of isotopes

|-| ?^[1] | style="text-align:center" | 5| style="text-align:center" | 1| | p-unstable| 2p?| ?| 2−#|||-| | style="text-align:center" | 5| style="text-align:center" | 2| |
[{{val|801|(20)|u=keV}}]| p| ^[2] | (3/2−)|||-| ^{[3] [4]} | style="text-align:center" | 5| style="text-align:center" | 3| | | β⁺α| | 2+|||-| style="text-indent:1em" | | colspan="3" style="text-indent:2em" | | | | | 0+|||-| | style="text-align:center" | 5| style="text-align:center" | 4| | | p| | ^[5] | 3/2−|||-| ^[6] | style="text-align:center" | 5| style="text-align:center" | 5| | colspan=3 align=center|Stable| 3+| colspan=2 align=center|[{{val|0.189}}, {{val|0.204}}]^[7] |-| | style="text-align:center" | 5| style="text-align:center" | 6| | colspan=3 align=center|Stable| 3/2−| colspan=2 align=center|[{{val|0.796}}, {{val|0.811}}]|-| style="text-indent:1em" | | colspan="3" style="text-indent:2em" | | | | | 1/2+, (3/2+)|||-| rowspan=2|| rowspan=2 style="text-align:center" | 5| rowspan=2 style="text-align:center" | 7| rowspan=2|| rowspan=2|| β⁻ | | rowspan=2|1+| rowspan=2|| rowspan=2||-| β⁻α | ^[8] |-| rowspan=2|| rowspan=2 style="text-align:center" | 5| rowspan=2 style="text-align:center" | 8| rowspan=2|| rowspan=2|| β⁻ | | rowspan=2|3/2−| rowspan=2|| rowspan=2||-| β⁻n | |-| rowspan=3|| rowspan=3 style="text-align:center" | 5| rowspan=3 style="text-align:center" | 9| rowspan=3|| rowspan=3|| β⁻ | | rowspan=3|2−| rowspan=3|| rowspan=3||-| β⁻n | |-| β⁻2n ?^[9] | ?|-| style="text-indent:1em" | | colspan="3" style="text-indent:2em" | | | IT ?| | 0+|||-| rowspan=3|| rowspan=3 style="text-align:center" | 5| rowspan=3 style="text-align:center" | 10| rowspan=3|| rowspan=3|| β⁻n | | rowspan=3|3/2−| rowspan=3|| rowspan=3||-| β⁻ (<)| |-| β⁻2n (<)| |-| | style=text-align:center | 5| style=text-align:center | 11| | > | n ?| ?| 0−|||-| rowspan=5|^[10] | rowspan=5 style=text-align:center | 5| rowspan=5 style=text-align:center | 12| rowspan=5|| rowspan=5|| β⁻n | | rowspan=5|(3/2−)| rowspan=5|| rowspan=5||-| β⁻ | |-| β⁻2n | |-| β⁻3n | |-| β⁻4n | |-| | style=text-align:center | 5| style=text-align:center | 13| | < | n| | (2−)|||-| rowspan=4|| rowspan=4 style=text-align:center | 5| rowspan=4 style=text-align:center | 14| rowspan=4|| rowspan=4|| β⁻n | | rowspan=4|(3/2−)| rowspan=4|| rowspan=4||-| β⁻2n | |-| β⁻3n (<)| |-| β⁻ (>)| |-| ^[11] | style=text-align:center | 5| style=text-align:center | 15| | > | n| | (1−, 2−)|||-| | style=text-align:center | 5| style=text-align:center | 16| | > | 2n| | (3/2−)||

Boron-8

Boron-8 is an isotope of boron that undergoes β⁺ decay to beryllium-8 with a half-life of . It is the strongest candidate for a halo nucleus with a loosely-bound proton, in contrast to neutron halo nuclei such as lithium-11.^[12]

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,^[13] and are an important background to dark matter direct detection experiments.^[14] 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

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

Notes and References

1. This isotope has not yet been observed; given data is inferred or estimated from periodic trends.
2. Subsequently decays by double proton emission to for a net reaction of → + 3
3. Has 1 halo proton
4. Intermediate product of a branch of proton-proton chain in stellar nucleosynthesis as part of the process converting hydrogen to helium
5. Immediately decays into two α particles, for a net reaction of → 2 +
6. One of the few stable odd-odd nuclei
7. Web site: Atomic Weight of Boron. CIAAW.
8. Immediately decays into two α particles, for a net reaction of → 3 +
9. Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
10. Has 2 halo neutrons
11. Leblond. S.. etal. First observation of ²⁰B and ²¹B. Physical Review Letters. 121. 26. 262502–1–262502–6. 10.1103/PhysRevLett.121.262502. 30636115. 1901.00455. 2018. 58602601.
12. Maaß . Bernhard . Müller . Peter . Nörtershäuser . Wilfried . Clark . Jason . Gorges . Christian . Kaufmann . Simon . König . Kristian . Krämer . Jörg . Levand . Anthony . Orford . Rodney . Sánchez . Rodolfo . Savard . Guy . Sommer . Felix . Towards laser spectroscopy of the proton-halo candidate boron-8 . Hyperfine Interactions . November 2017 . 238 . 1 . 25 . 10.1007/s10751-017-1399-5. 2017HyInt.238...25M . 254551036 .
13. A. . Bellerive . 2004 . Review of solar neutrino experiments . International Journal of Modern Physics A . 19 . 8 . 1167–1179 . 2004IJMPA..19.1167B . hep-ex/0312045 . 10.1142/S0217751X04019093. 16980300 .
14. Cerdeno. David G.. Fairbairn. Malcolm. Jubb. Thomas. Machado. Pedro. Vincent. Aaron C.. Boehm. Celine. Physics from solar neutrinos in dark matter direct detection experiments. JHEP. 2016. 2016. 5. 118. 10.1007/JHEP05(2016)118. 1604.01025. 2016JHEP...05..118C. 55112052.