Isotopes of berkelium (₉₇Bk)

Main isotopes^[1]			Decay
	abundance	half-life (t_1/2)	mode	product
²⁴⁵Bk	synth	4.94 d	ε	²⁴⁵Cm
²⁴⁵Bk	synth	4.94 d	α	²⁴¹Am
²⁴⁶Bk	synth	1.8 d	α	²⁴²Am
²⁴⁶Bk	synth	1.8 d	β⁺	²⁴⁶Cm
²⁴⁷Bk	synth	1380 y	α	²⁴³Am
²⁴⁸Bk	synth	>300 y^[2]	α	²⁴⁴Am
²⁴⁹Bk	synth	330 d	β⁻	²⁴⁹Cf
			α	²⁴⁵Am
			SF	–

Berkelium (₉₇Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was ²⁴³Bk in 1949. There are 20 known radioisotopes, from ²³⁰Bk and ²³³Bk to ²⁵³Bk (with the exception of ²³⁵Bk and ²³⁷Bk), and 6 nuclear isomers. The longest-lived isotope is ²⁴⁷Bk with a half-life of 1,380 years.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life	Decay mode ^{[n 4]}	Daughter isotope	Spin and parity ^{[n 5]}^{[n 6]}
Nuclide ^{[n 1]}	Excitation energy^{[n 6]}			Half-life	Decay mode ^{[n 4]}	Daughter isotope	Spin and parity ^{[n 5]}^{[n 6]}
²³⁰Bk^[3]	97	133		~0.46 s	α	²²⁶Am
²³³Bk^[4]	97	136		21+48 −17 s	α	²²⁹Am	3/2-#
²³⁴Bk^[5]	97	137		19+6 −4 s	β⁺	²³⁴Cm	3-#
					β⁺, SF	(various)
					α	²³⁰Am
²³⁶Bk^[6]	97	139	236.05733(43)#	22+13 −6 s	β⁺ (96%)	²³⁶Cm	4+#
²³⁶Bk^[6]	97	139	236.05733(43)#	22+13 −6 s	β⁺, SF (4%)	(various)	4+#
²³⁸Bk	97	141	238.05828(31)#	2.40(8) min	β⁺	²³⁸Cm	1#
					β⁺, SF (0.048%)	(various)
					α (rare)	²³⁴Am
²³⁹Bk^[7]	97	142	239.05828(25)#	100# s	β⁺ (>99%)	²³⁹Cm	(7/2+)
					α (<1%)	²³⁵Am
					SF (<1%)	(various)
²⁴⁰Bk	97	143	240.05976(16)#	4.8(8) min	β⁺	²⁴⁰Cm	7-#
					β⁺, SF (0.002%)	(various)
					α (rare)	²³⁶Am
²⁴¹Bk^[8]	97	144	241.06023(22)#	4.6(4) min	β⁺	²⁴¹Cm	(7/2+)
²⁴¹Bk^[8]	97	144	241.06023(22)#	4.6(4) min	α (rare)	²³⁷Am	(7/2+)
²⁴²Bk	97	145	242.06198(22)#	7.0(13) min	β⁺	²⁴²Cm	2−#
²⁴²Bk	97	145	242.06198(22)#	7.0(13) min	β⁺, SF (<3×10⁻⁵%)	(various)	2−#
^242mBk	200(200)# keV			600(100) ns	SF	(various)
²⁴³Bk	97	146	243.063008(5)	4.5(2) h	β⁺ (99.85%)	²⁴³Cm	(3/2−)
²⁴³Bk	97	146	243.063008(5)	4.5(2) h	α (.15%)	²³⁹Am	(3/2−)
²⁴⁴Bk	97	147	244.065181(16)	4.35(15) h	β⁺ (99.99%)	²⁴⁴Cm	(4−)#
²⁴⁴Bk	97	147	244.065181(16)	4.35(15) h	α (.006%)	²⁴⁰Am	(4−)#
²⁴⁵Bk	97	148	245.0663616(25)	4.94(3) d	EC (99.88%)	²⁴⁵Cm	3/2−
²⁴⁵Bk	97	148	245.0663616(25)	4.94(3) d	α (.12%)	²⁴¹Am	3/2−
²⁴⁶Bk	97	149	246.06867(6)	1.80(2) d	β⁺ (99.8%)	²⁴⁶Cm	2(−)
²⁴⁶Bk	97	149	246.06867(6)	1.80(2) d	α (.2%)	²⁴²Am	2(−)
²⁴⁷Bk	97	150	247.070307(6)	1.38(25)×10³ y	α	²⁴³Am	(3/2−)
²⁴⁷Bk	97	150	247.070307(6)	1.38(25)×10³ y	SF (rare)	(various)	(3/2−)
²⁴⁸Bk	97	151	248.07309(8)#	>300 y^[9]	α	²⁴⁴Am	6+#
^248mBk	30(70)# keV			23.7(2) h	β⁻	²⁴⁸Cf	1(−)
²⁴⁹Bk^{[n 7]}	97	152	249.0749867(28)	330(4) d	β⁻	²⁴⁹Cf	7/2+
					α (.00145%)	²⁴⁵Am
					SF (4.7×10⁻⁸%)	(various)
^249mBk	8.80(10) keV			300 μs	IT	²⁴⁹Bk	(3/2−)
²⁵⁰Bk	97	153	250.078317(4)	3.212(5) h	β⁻	²⁵⁰Cf	2−
^250m1Bk	35.59(5) keV			29(1) μs	IT	²⁵⁰Bk	(4+)
^250m2Bk	84.1(21) keV			213(8) μs			(7+)
²⁵¹Bk	97	154	251.080760(12)	55.6(11) min	β⁻	²⁵¹Cf	(3/2−)#
²⁵¹Bk	97	154	251.080760(12)	55.6(11) min	α (10⁻⁵%)	²⁴⁷Am	(3/2−)#
^251mBk	35.5(13) keV			58(4) μs	IT	²⁵¹Bk	(7/2+)#
²⁵²Bk	97	155	252.08431(22)#	1.8(5) min	β⁻	²⁵²Cf
²⁵²Bk	97	155	252.08431(22)#	1.8(5) min	α	²⁴⁸Am
²⁵³Bk	97	156	253.08688(39)#	10# min	β⁻	²⁵³Cf
This table header & footer: view

^ ^mBk – 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:

EC: Electron capture

SF: Spontaneous fission
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ ^a ^b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^ Easiest isotope to synthesize

Actinides vs fission products

Actinides and fission products by half-life v t e
Actinides^[10] by decay chain				Half-life range (a)	Fission products of ²³⁵U by yield^[11]
4n	4n + 1	4n + 2	4n + 3	Half-life range (a)	4.5–7%	0.04–1.25%	<0.001%
²²⁸Ra^№				4–6 a		¹⁵⁵Eu^þ
²⁴⁴Cm^ƒ	²⁴¹Pu^ƒ	²⁵⁰Cf	²²⁷Ac^№	10–29 a	⁹⁰Sr	⁸⁵Kr	^113mCd^þ
²³²U^ƒ		²³⁸Pu^ƒ	²⁴³Cm^ƒ	29–97 a	¹³⁷Cs	¹⁵¹Sm^þ	^121mSn
²⁴⁸Bk^[12]	²⁴⁹Cf^ƒ	^242mAm^ƒ		141–351 a	No fission products have a half-life in the range of 100 a–210 ka ...
	²⁴¹Am^ƒ		²⁵¹Cf^ƒ^[13]	430–900 a
		²²⁶Ra^№	²⁴⁷Bk	1.3–1.6 ka
²⁴⁰Pu	²²⁹Th	²⁴⁶Cm^ƒ	²⁴³Am^ƒ	4.7–7.4 ka
	²⁴⁵Cm^ƒ	²⁵⁰Cm		8.3–8.5 ka
			²³⁹Pu^ƒ	24.1 ka
		²³⁰Th^№	²³¹Pa^№	32–76 ka
²³⁶Np^ƒ	²³³U^ƒ	²³⁴U^№		150–250 ka	⁹⁹Tc^₡	¹²⁶Sn
²⁴⁸Cm		²⁴²Pu		327–375 ka		⁷⁹Se^₡
				1.53 Ma	⁹³Zr
	²³⁷Np^ƒ			2.1–6.5 Ma	¹³⁵Cs^₡	¹⁰⁷Pd
²³⁶U			²⁴⁷Cm^ƒ	15–24 Ma		¹²⁹I^₡
²⁴⁴Pu				80 Ma	... nor beyond 15.7 Ma^[14]
²³²Th^№		²³⁸U^№	²³⁵U^ƒ№	0.7–14.1 Ga	... nor beyond 15.7 Ma^[14]
₡, has thermal neutron capture cross section in the range of 8–50 barns ƒ, fissile №, primarily a naturally occurring radioactive material (NORM) þ, neutron poison (thermal neutron capture cross section greater than 3k barns)

References

^ 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.
^ Milsted, J.; Friedman, A. M.; Stevens, C. M. (1965). "The alpha half-life of berkelium-247; a new long-lived isomer of berkelium-248". Nuclear Physics. 71 (2): 299. doi:10.1016/0029-5582(65)90719-4.
^ Heinz, Sophie. "Observation of new neutron-deficient multinucleon transfer reactions isotopes with Z ≥ 92 in multinucleon transfer reactions". Slideplayer. GSI Helmholtzzentrum and Justus-Liebig-Universität Gießen. Retrieved 23 June 2023.
^ Devaraja, H. M.; Heinz, S.; Beliuskina, O.; Comas, V.; Hofmann, S.; Hornung, C.; Münzenberg, G.; Nishio, K.; Ackermann, D.; Gambhir, Y. K.; Gupta, M.; Henderson, R. A.; Heßberger, F. P.; Khuyagbaatar, J.; Kindler, B.; Lommel, B.; Moody, K. J.; Maurer, J.; Mann, R.; Popeko, A. G.; Shaughnessy, D. A.; Stoyer, M. A.; Yeremin, A. V. (2 September 2015). "Observation of new neutron-deficient isotopes with Z≥92 in multinucleon transfer reactions" (PDF). Physics Letters B. 748: 199–203. Bibcode:2015PhLB..748..199D. doi:10.1016/j.physletb.2015.07.006. ISSN 0370-2693. Retrieved 23 June 2023.
^ Kaji, D.; Morimoto, K.; Haba, H.; Ideguchi, E.; Koura, H.; Morita, K. (2016). "Decay Properties of New Isotopes ²³⁴Bk and ²³⁰Am, and Even–Even Nuclides ²³⁴Cm and ²³⁰Pu" (PDF). Journal of the Physical Society of Japan. 84 (15002): 015002. Bibcode:2016JPSJ...85a5002K. doi:10.7566/JPSJ.85.015002.
^ Konki, J.; et al. (10 Jan 2017). "Towards saturation of the electron-capture delayed fission probability: The new isotopes ²⁴⁰Es and ²³⁶Bk". Physics Letters B. 764: 265–270. Bibcode:2017PhLB..764..265K. doi:10.1016/j.physletb.2016.11.038. hdl:1885/110868. ISSN 0370-2693.
^ Antalic, S.; Heßberger, F. P.; Hofmann, S.; et al. (2010). "Studies of neutron-deficient mendelevium isotopes at SHIP". European Physical Journal A. 43 (1): 35–44. Bibcode:2010EPJA...43...35A. doi:10.1140/epja/i2009-10896-0. S2CID 121963345.
^ Asai, M.; Tsukada, K.; Ichikawa, S.; Sakama, M.; Haba, H.; Nagame, Y.; Nishinaka, I.; Akiyama, K.; Toyoshima, A.; Kaneko, T.; Oura, Y.; Kojima, Y.; Shibata, M. (1 January 2003). "Identification of the new isotope 241Bk" (PDF). The European Physical Journal A - Hadrons and Nuclei. 16 (1): 17–19. Bibcode:2003EPJA...16...17A. doi:10.1140/epja/i2002-10112-y. ISSN 1434-601X. S2CID 122786530. Retrieved 25 June 2023.
^ Milsted, J.; Friedman, A. M.; Stevens, C. M. (1965). "The alpha half-life of berkelium-247; a new long-lived isomer of berkelium-248". Nuclear Physics. 71 (2): 299. Bibcode:1965NucPh..71..299M. doi:10.1016/0029-5582(65)90719-4.
^ Plus radium (element 88). While actually a sub-actinide, it immediately precedes actinium (89) and follows a three-element gap of instability after polonium (84) where no nuclides have half-lives of at least four years (the longest-lived nuclide in the gap is radon-222 with a half life of less than four days). Radium's longest lived isotope, at 1,600 years, thus merits the element's inclusion here.
^ Specifically from thermal neutron fission of uranium-235, e.g. in a typical nuclear reactor.
^ Milsted, J.; Friedman, A. M.; Stevens, C. M. (1965). "The alpha half-life of berkelium-247; a new long-lived isomer of berkelium-248". Nuclear Physics. 71 (2): 299. Bibcode:1965NucPh..71..299M. doi:10.1016/0029-5582(65)90719-4.
"The isotopic analyses disclosed a species of mass 248 in constant abundance in three samples analysed over a period of about 10 months. This was ascribed to an isomer of Bk²⁴⁸ with a half-life greater than 9 [years]. No growth of Cf²⁴⁸ was detected, and a lower limit for the β⁻ half-life can be set at about 10⁴ [years]. No alpha activity attributable to the new isomer has been detected; the alpha half-life is probably greater than 300 [years]."
^ This is the heaviest nuclide with a half-life of at least four years before the "sea of instability".
^ Excluding those "classically stable" nuclides with half-lives significantly in excess of ²³²Th; e.g., while ^113mCd has a half-life of only fourteen years, that of ¹¹³Cd is nearly eight quadrillion years.

Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

List of isotopes

Actinides vs fission products

See also

References