Isotopes of boron

Isotopes of boron (₅B)
Standard atomic weight Ar°(B)
	[10.806, 10.821]; 10.81±0.02 (abridged);
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Boron (₅B) naturally occurs as isotopes ¹⁰
B
and ¹¹
B
, 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 ⁸
B
, with a half-life of only 771.9(9) ms and ¹²
B
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 ⁷
B
and ⁹
B
) while those with mass above 11 mostly become carbon.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da)^[3] ^{[n 2]}^{[n 3]}	Half-life^[4] [resonance width]	Decay mode^[4] ^{[n 4]}	Daughter isotope ^{[n 5]}	Spin and parity^[4] ^{[n 6]}^{[n 7]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy			Half-life^[4] [resonance width]	Decay mode^[4] ^{[n 4]}	Daughter isotope ^{[n 5]}	Spin and parity^[4] ^{[n 6]}^{[n 7]}	Normal proportion^[4]	Range of variation
⁶ B ?^{[n 8]}	5	1	6.050800(2150)	p-unstable	2p?	⁴ Li ?	2−#
⁷ B	5	2	7.029712(27)	570(14) ys [801(20) keV]	p	⁶ Be ^{[n 9]}	(3/2−)
⁸ B ^{[n 10]}^{[n 11]}	5	3	8.0246073(11)	771.9(9) ms	β α	⁴ He	2
^8m B	10624(8) keV						0
⁹ B	5	4	9.0133296(10)	800(300) zs	p	⁸ Be ^{[n 12]}	3/2−
¹⁰ B ^{[n 13]}	5	5	10.012936862(16)	Stable			3	[0.189, 0.204]^[5]
¹¹ B	5	6	11.009305167(13)	Stable			3/2−	[0.796, 0.811]^[5]
^11m B	12560(9) keV						1/2 , (3/2 )
¹² B	5	7	12.0143526(14)	20.20(2) ms	β⁻ (99.40(2)%)	¹² C	1
¹² B	5	7	12.0143526(14)	20.20(2) ms	β⁻α (0.60(2)%)	⁸ Be ^{[n 14]}	1
¹³ B	5	8	13.0177800(11)	17.16(18) ms	β⁻ (99.734(36)%)	¹³ C	3/2−
¹³ B	5	8	13.0177800(11)	17.16(18) ms	β⁻n (0.266(36)%)	¹² C	3/2−
¹⁴ B	5	9	14.025404(23)	12.36(29) ms	β⁻ (93.96(23)%)	¹⁴ C	2−
					β⁻n (6.04(23)%)	¹³ C
					β⁻2n ?^{[n 15]}	¹² C ?
^14m B	17065(29) keV			4.15(1.90) zs	IT ?^{[n 15]}		0
¹⁵ B	5	10	15.031087(23)	10.18(35) ms	β⁻n (98.7(1.0)%)	¹⁴ C	3/2−
					β⁻ (< 1.3%)	¹⁵ C
					β⁻2n (< 1.5%)	¹³ C
¹⁶ B	5	11	16.039841(26)	> 4.6 zs	n ?^{[n 15]}	¹⁵ B ?	0−
¹⁷ B ^{[n 16]}	5	12	17.04693(22)	5.08(5) ms	β⁻n (63(1)%)	¹⁶ C	(3/2−)
					β⁻ (21.1(2.4)%)	¹⁷ C
					β⁻2n (12(2)%)	¹⁵ C
					β⁻3n (3.5(7)%)	¹⁴ C
					β⁻4n (0.4(3)%)	¹³ C
¹⁸ B	5	13	18.05560(22)	< 26 ns	n	¹⁷ B	(2−)
¹⁹ B ^{[n 16]}	5	14	19.06417(56)	2.92(13) ms	β⁻n (71(9)%)	¹⁸ C	(3/2−)
					β⁻2n (17(5)%)	¹⁷ C
					β⁻3n (< 9.1%)	¹⁶ C
					β⁻ (> 2.9%)	¹⁹ C
²⁰ B ^[6]	5	15	20.07451(59)	> 912.4 ys	n	¹⁹ B	(1−, 2−)
²¹ B ^[6]	5	16	21.08415(60)	> 760 ys	2n	¹⁹ B	(3/2−)
This table header & footer: view

^ ^mB – Excited nuclear isomer.
^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
^ Modes of decay:

n: Neutron emission

p: Proton emission
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^ This isotope has not yet been observed; given data is inferred or estimated from periodic trends.
^ Subsequently decays by double proton emission to ⁴
He
for a net reaction of ⁷
B
→ ⁴
He
3 ¹
H
^ Has 1 halo proton
^ Intermediate product of a branch of proton-proton chain in stellar nucleosynthesis as part of the process converting hydrogen to helium
^ Immediately decays into two α particles, for a net reaction of ⁹
B
→ 2 ⁴
He
¹
H
^ One of the few stable odd-odd nuclei
^ Immediately decays into two α particles, for a net reaction of ¹²
B
→ 3 ⁴
He
e⁻
^ ^a ^b ^c Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
^ ^a ^b 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 candidate for a halo nucleus with a loosely-bound proton, in contrast to neutron halo nuclei such as lithium-11.^[7]

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,^[8] and are an important background to dark matter direct detection experiments.^[9] 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

^ "Standard Atomic Weights: Boron". CIAAW. 2009.
^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
^ ^a ^b ^c ^d Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^ ^a ^b "Atomic Weight of Boron". CIAAW.
^ ^a ^b Leblond, S.; et al. (2018). "First observation of ²⁰B and ²¹B". Physical Review Letters. 121 (26): 262502–1–262502–6. arXiv:1901.00455. doi:10.1103/PhysRevLett.121.262502. PMID 30636115. S2CID 58602601.
^ 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 (November 2017). "Towards laser spectroscopy of the proton-halo candidate boron-8". Hyperfine Interactions. 238 (1): 25. Bibcode:2017HyInt.238...25M. doi:10.1007/s10751-017-1399-5. S2CID 254551036.
^ Bellerive, A. (2004). "Review of solar neutrino experiments". International Journal of Modern Physics A. 19 (8): 1167–1179. arXiv:hep-ex/0312045. Bibcode:2004IJMPA..19.1167B. doi:10.1142/S0217751X04019093. S2CID 16980300.
^ 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. arXiv:1604.01025. Bibcode:2016JHEP...05..118C. doi:10.1007/JHEP05(2016)118. S2CID 55112052.

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

[3] B – Excited nuclear isomer.

[5] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-6] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[8] Modes of decay:

n: Neutron emission

p: Proton emission

[9] Bold symbol as daughter – Daughter product is stable.

[10] ( ) spin value – Indicates spin with weak assignment arguments.

[TNN-11] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[unconfirmed-12] This isotope has not yet been observed; given data is inferred or estimated from periodic trends.

[13] Subsequently decays by double proton emission to ⁴
He
for a net reaction of ⁷
B
→ ⁴
He
3 ¹
H

[14] Has 1 halo proton

[15] Intermediate product of a branch of proton-proton chain in stellar nucleosynthesis as part of the process converting hydrogen to helium

[16] Immediately decays into two α particles, for a net reaction of ⁹
B
→ 2 ⁴
He
¹
H

[17] One of the few stable odd-odd nuclei

[19] Immediately decays into two α particles, for a net reaction of ¹²
B
→ 3 ⁴
He
e⁻

[decay_mode_1-20] Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

[hn-21] Has 2 halo neutrons

[1] "Standard Atomic Weights: Boron". CIAAW. 2009.

[CIAAW2021-2] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

[AME2020_II-4] Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.

[NUBASE2020-7] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[Atomic_Weight_of_Boron2-18] "Atomic Weight of Boron". CIAAW.

[20B-21B-22] Leblond, S.; et al. (2018). "First observation of ²⁰B and ²¹B". Physical Review Letters. 121 (26): 262502–1–262502–6. arXiv:1901.00455. doi:10.1103/PhysRevLett.121.262502. PMID 30636115. S2CID 58602601.

[23] 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 (November 2017). "Towards laser spectroscopy of the proton-halo candidate boron-8". Hyperfine Interactions. 238 (1): 25. Bibcode:2017HyInt.238...25M. doi:10.1007/s10751-017-1399-5. S2CID 254551036.

[Bellerive2004-24] Bellerive, A. (2004). "Review of solar neutrino experiments". International Journal of Modern Physics A. 19 (8): 1167–1179. arXiv:hep-ex/0312045. Bibcode:2004IJMPA..19.1167B. doi:10.1142/S0217751X04019093. S2CID 16980300.

[8B-Cerdeno-25] 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. arXiv:1604.01025. Bibcode:2016JHEP...05..118C. doi:10.1007/JHEP05(2016)118. S2CID 55112052.

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