Isótopos de boro

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Isótopos principales de boro ( ₅ B)

Isótopo			Decaer
	abundancia	vida media ( t _1/2 )	modo	producto
¹⁰ B	20%	estable ^[1]
¹¹ B	80%	estable ^[1]

^El contenido de ¹⁰ B puede ser tan bajo como 19,1% y tan alto como 20,3% en muestras naturales. ¹¹ B es el resto en tales casos. ^[2]

Peso atómico estándar A r, estándar (B)

[10.806, 10.821] ^[3]
Convencional: 10,81

El boro ( ₅ B) se encuentra naturalmente como isótopos ¹⁰ B y ¹¹ B, el último de los cuales constituye aproximadamente el 80% del boro natural. Hay 13 radioisótopos que se han descubierto, con números de masa de 7 a 21, todos con vidas medias cortas , siendo la más larga la de ⁸ B, con una vida media de solo 770 milisegundos (ms) y ¹² B con media vida útil. -vida de 20,2 ms. Todos los demás isótopos tienen vidas medias inferiores a 17,35 ms. Aquellos isótopos con masa por debajo de 10 se descomponen en helio (a través de isótopos de berilio de vida corta para ⁷ B y ⁹B) mientras que aquellos con una masa superior a 11 se convierten en su mayoría en carbono .

Un gráfico que muestra la abundancia de los isótopos de boro naturales.

Lista de isótopos [ editar ]

Nuclido ^[4] ^{[n 1]}	Z	norte	Masa isotópica ( Da ) ^[5]^{[n 2]}^{[n 3]}	Vida media [ ancho de resonancia ]	Modo de caída ^{[n 4]}	Hija isótopo ^{[n 5]}	Spin y paridad ^{[n 6]}^{[n 7]}	Abundancia natural (fracción molar)
Nuclido ^[4] ^{[n 1]}	Energía de excitación			Vida media [ ancho de resonancia ]	Modo de caída ^{[n 4]}	Hija isótopo ^{[n 5]}	Spin y paridad ^{[n 6]}^{[n 7]}	Normal proportion	Range of variation
⁷B	5	2	7.029712(27)	570(14) × 10⁻²⁴ s [801(20) keV]	p	⁶ Be ^{[n 8]}	(3/2−)
⁸B^{[n 9]}	5	3	8.0246073(11)	770(3) ms	β+, α	2 ⁴ He	2+
⁹B	5	4	9.0133296(10)	800(300) × 10⁻²¹ s [0.54(21) keV]	p, α	2 ⁴ He	3/2−
¹⁰B^{[n 10]}	5	5	10.012936862(16)	Stable			3+	0.199(7)	18.929–20.386
¹¹B	5	6	11.009305167(13)	Stable			3/2−	0.801(7)	79.614–81.071
¹²B	5	7	12.0143526(14)	20.20(2) ms	β⁻ (98.4%)	¹² C	1+
¹²B	5	7	12.0143526(14)	20.20(2) ms	β⁻, α (1.6%)	⁸ Be ^{[n 11]}	1+
¹³B	5	8	13.0177800(11)	17.33(17) ms	β⁻ (99.72%)	¹³ C	3/2−
¹³B	5	8	13.0177800(11)	17.33(17) ms	β⁻, n (0.28%)	¹² C	3/2−
¹⁴B	5	9	14.025404(23)	12.5(5) ms	β⁻ (93.96%)	¹⁴ C	2−
¹⁴B	5	9	14.025404(23)	12.5(5) ms	β⁻, n (6.04%)	¹³ C	2−
¹⁵B	5	10	15.031088(23)	9.93(7) ms	β⁻, n (93.6%)	¹⁴ C	3/2−
					β⁻ (6.0%)	¹⁵ C
					β⁻, 2n (0.4%)	¹³ C
¹⁶B	5	11	16.039842(26)	> 4.6 × 10⁻²¹ s	n	¹⁵ B	0−
¹⁷B^{[n 12]}	5	12	17.04693(22)	5.08(5) ms	β⁻, n (63.0%)	¹⁶ C	(3/2−)
					β⁻ (22.1%)	¹⁷ C
					β⁻, 2n (11.0%)	¹⁵ C
					β⁻, 3n (3.5%)	¹⁴ C
					β⁻, 4n (0.4%)	¹³ C
¹⁸B	5	13	18.05560(22)	< 26 ns	n	¹⁷ B	(2−)
¹⁹B^{[n 12]}	5	14	19.06417(56)	2.92(13) ms	β⁻, n (71%)	¹⁸ C	3/2−#
					β⁻, 2n (17%)	¹⁷ C
					β⁻ (12%)	¹⁹ C
²⁰B^[6]	5	15	20.07348(86)#	[2.50(9) MeV]	n	¹⁹ B	(1−, 2−)
²¹B^[6]	5	16	21.08302(97)#	< 260 ns [2.47(19) MeV]	2n	¹⁹ B	(3/2−)#

^ ^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).
^ Subsequently decays by double proton emission to ⁴He for a net reaction of ⁷B → ⁴He + 3 ¹H
^ Has 1 halo proton
^ One of the few stable odd-odd nuclei
^ Immediately decays into two α particles, for a net reaction of ¹²B → 3 ⁴He + e⁻
^ a b Has 2 halo neutrons

Neutrinos from boron-8 beta decays within the sun are an important background to dark matter direct detection experiments.^[7] They are the first component of the neutrino floor that dark matter direct detection experiments are expected to eventually encounter.

Applications[edit]

Boron-10[edit]

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

References[edit]

^ a b "Atomic Weights and Isotopic Compositions for All Elements". National Institute of Standards and Technology. Retrieved 2008-09-21.
^ 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.
^ Meija, Juris; 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.
^ Half-life, decay mode, nuclear spin, and isotopic composition is sourced in:
Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
^ Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references" (PDF). Chinese Physics C. 41 (3): 030003-1–030003-442. doi:10.1088/1674-1137/41/3/030003.
^ 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.
^ 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.

[5] B – Excited nuclear isomer.

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

[TMS-8] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[9] Modes of decay:
n: Neutron emission
p: Proton emission

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

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

[TNN-12] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

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

[14] Has 1 halo proton

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

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

[hn-17] Has 2 halo neutrons

[NISTic-1] "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.

[CIAAW2013-3] Meija, Juris; 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] Half-life, decay mode, nuclear spin, and isotopic composition is sourced in:
Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.

[6] Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references" (PDF). Chinese Physics C. 41 (3): 030003-1–030003-442. doi:10.1088/1674-1137/41/3/030003.

[20b21-18] 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.

[19] 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.

[1]

n:	Neutron emission
p:	Proton emission