Isotopes of manganese (₂₅Mn)

Main isotopes^[1]			Decay
	abundance	half-life (t_1/2)	mode	product
⁵²Mn	synth	5.591 d	β⁺	⁵²Cr
⁵³Mn	trace	3.7×10⁶ y	ε	⁵³Cr
⁵⁴Mn	synth	312.081 d	ε	⁵⁴Cr
			β⁻	⁵⁴Fe
			β⁺	⁵⁴Cr
⁵⁵Mn	100%	stable

Standard atomic weight A_r°(Mn)

54.938043±0.000002^[2]
54.938±0.001 (abridged)^[3]

Naturally occurring manganese (₂₅Mn) is composed of one stable isotope, ⁵⁵Mn. 26 radioisotopes have been characterized, with the most stable being ⁵³Mn with a half-life of 3.7 million years, ⁵⁴Mn with a half-life of 312.3 days, and ⁵²Mn with a half-life of 5.591 days. All of the remaining radioactive isotopes have half-lives that are less than 3 hours and the majority of these have half-lives that are less than a minute. This element also has 3 meta states.

Manganese is part of the iron group of elements, which are thought to be synthesized in large stars shortly before supernova explosions. ⁵³Mn decays to ⁵³Cr with a half-life of 3.7 million years. Because of its relatively short half-life, ⁵³Mn occurs only in tiny amounts due to the action of cosmic rays on iron in rocks.^[4] Manganese isotopic contents are typically combined with chromium isotopic contents and have found application in isotope geology and radiometric dating. Mn−Cr isotopic ratios reinforce the evidence from ²⁶Al and ¹⁰⁷Pd for the early history of the Solar System. Variations in ⁵³Cr/⁵²Cr and Mn/Cr ratios from several meteorites indicate an initial ⁵³Mn/⁵⁵Mn ratio that suggests Mn−Cr isotopic systematics must result from in-situ decay of ⁵³Mn in differentiated planetary bodies. Hence ⁵³Mn provides additional evidence for nucleosynthetic processes immediately before coalescence of the Solar System.

The isotopes of manganese range in atomic weight from 46 u (⁴⁶Mn) to 72 u (⁷²Mn). The primary decay mode before the most abundant stable isotope, ⁵⁵Mn, is electron capture and the primary mode after is beta decay.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life	Decay mode ^{[n 4]}	Daughter isotope ^{[n 5]}	Spin and parity ^{[n 6]}^{[n 7]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 7]}			Half-life	Decay mode ^{[n 4]}	Daughter isotope ^{[n 5]}	Spin and parity ^{[n 6]}^{[n 7]}	Normal proportion	Range of variation
⁴⁶Mn	25	21	45.98672(12)#	37(3) ms	β⁺ (78%)	⁴⁶Cr	(4+)
					β⁺, p (22%)	⁴⁵V
					β⁺, α (<1%)	⁴²Ti
					β⁺, 2p (<1%)	⁴⁴Ti
^46mMn	150(100)# keV			1# ms	β⁺	⁴⁶Cr	1-#
⁴⁷Mn	25	22	46.97610(17)#	100(50) ms	β⁺ (96.6%)	⁴⁷Cr	5/2−#
⁴⁷Mn	25	22	46.97610(17)#	100(50) ms	β⁺, p (3.4%)	⁴⁶V	5/2−#
⁴⁸Mn	25	23	47.96852(12)	158.1(22) ms	β⁺ (99.71%)	⁴⁸Cr	4+
					β⁺, p (.027%)	⁴⁷V
					β⁺, α (6×10⁻⁴%)	⁴⁴Ti
⁴⁹Mn	25	24	48.959618(26)	382(7) ms	β⁺	⁴⁹Cr	5/2−
⁵⁰Mn	25	25	49.9542382(11)	283.29(8) ms	β⁺	⁵⁰Cr	0+
^50mMn	229(7) keV			1.75(3) min	β⁺	⁵⁰Cr	5+
⁵¹Mn	25	26	50.9482108(11)	46.2(1) min	β⁺	⁵¹Cr	5/2−
⁵²Mn	25	27	51.9455655(21)	5.591(3) d	β⁺	⁵²Cr	6+
^52mMn	377.749(5) keV			21.1(2) min	β⁺ (98.25%)	⁵²Cr	2+
^52mMn	377.749(5) keV			21.1(2) min	IT (1.75%)	⁵²Mn	2+
⁵³Mn	25	28	52.9412901(9)	3.7(4)×10⁶ y	EC	⁵³Cr	7/2−	trace
⁵⁴Mn	25	29	53.9403589(14)	312.03(3) d	EC 99.99%	⁵⁴Cr	3+
					β⁻ (2.9×10⁻⁴%)	⁵⁴Fe
					β⁺ (5.76×10⁻⁷%)	⁵⁴Cr
⁵⁵Mn	25	30	54.9380451(7)	Stable			5/2−	1.0000
⁵⁶Mn	25	31	55.9389049(7)	2.5789(1) h	β⁻	⁵⁶Fe	3+
⁵⁷Mn	25	32	56.9382854(20)	85.4(18) s	β⁻	⁵⁷Fe	5/2−
⁵⁸Mn	25	33	57.93998(3)	3.0(1) s	β⁻	⁵⁸Fe	1+
^58mMn	71.78(5) keV			65.2(5) s	β⁻ (>99.9%)	⁵⁸Fe	(4)+
^58mMn	71.78(5) keV			65.2(5) s	IT (<.1%)	⁵⁸Mn	(4)+
⁵⁹Mn	25	34	58.94044(3)	4.59(5) s	β⁻	⁵⁹Fe	(5/2)−
⁶⁰Mn	25	35	59.94291(9)	51(6) s	β⁻	⁶⁰Fe	0+
^60mMn	271.90(10) keV			1.77(2) s	β⁻ (88.5%)	⁶⁰Fe	3+
^60mMn	271.90(10) keV			1.77(2) s	IT (11.5%)	⁶⁰Mn	3+
⁶¹Mn	25	36	60.94465(24)	0.67(4) s	β⁻	⁶¹Fe	(5/2)−
⁶²Mn	25	37	61.94843(24)	671(5) ms	β⁻ (>99.9%)	⁶²Fe	(3+)
⁶²Mn	25	37	61.94843(24)	671(5) ms	β⁻, n (<.1%)	⁶¹Fe	(3+)
^62mMn	0(150)# keV			92(13) ms			(1+)
⁶³Mn	25	38	62.95024(28)	275(4) ms	β⁻	⁶³Fe	5/2−#
⁶⁴Mn	25	39	63.95425(29)	88.8(25) ms	β⁻ (>99.9%)	⁶⁴Fe	(1+)
⁶⁴Mn	25	39	63.95425(29)	88.8(25) ms	β⁻, n (<.1%)	⁶³Fe	(1+)
^64mMn	135(3) keV			>100 µs
⁶⁵Mn	25	40	64.95634(58)	92(1) ms	β⁻ (>99.9%)	⁶⁵Fe	5/2−#
⁶⁵Mn	25	40	64.95634(58)	92(1) ms	β⁻, n (<.1%)	⁶⁴Fe	5/2−#
⁶⁶Mn	25	41	65.96108(43)#	64.4(18) ms	β⁻ (>99.9%)	⁶⁶Fe
⁶⁶Mn	25	41	65.96108(43)#	64.4(18) ms	β⁻, n (<.1%)	⁶⁵Fe
⁶⁷Mn	25	42	66.96414(54)#	45(3) ms	β⁻	⁶⁷Fe	5/2−#
⁶⁸Mn	25	43	67.96930(64)#	28(4) ms
⁶⁹Mn	25	44	68.97284(86)#	14(4) ms			5/2−#
⁷⁰Mn^[5]	25	45	69.978050(540)#	19.9(17) ms	β⁻=?	⁷⁰Fe	(4,5)
					β⁻, n?^{[n 8]}	⁶⁹Fe
					β⁻, 2n?^{[n 8]}	⁶⁸Fe
⁷¹Mn^[6]	25	46	70.982160(540)#	16# ms (>400 ns)	β⁻?^{[n 8]}	⁷¹Fe	5/2-#
					β⁻, n?^{[n 8]}	⁷⁰Fe
					β⁻, 2n?^{[n 8]}	⁶⁹Fe
⁷²Mn^[7]	25	47	71.988010(640)#	12# ms (>620 ns)	β⁻?^{[n 8]}	⁷²Fe
					β⁻, n?^{[n 8]}	⁷¹Fe
					β⁻, 2n?^{[n 8]}	⁷⁰Fe
⁷³Mn^[8]	25	48	72.992810(640)#	12# ms (>410 ns)	β⁻?^{[n 8]}	⁷³Fe	5/2−#
This table header & footer: view

^ ^mMn – 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

IT: Isomeric transition

n: Neutron emission

p: Proton emission
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) 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).
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

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.
^ "Standard Atomic Weights: Manganese". CIAAW. 2017.
^ 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.
^ J. Schaefer; et al. (2006). "Terrestrial manganese-53 — A new monitor of Earth surface processes". Earth and Planetary Science Letters. 251 (3–4): 334–345. Bibcode:2006E&PSL.251..334S. doi:10.1016/j.epsl.2006.09.016.
^ Tarasov, O. B.; et al. (April 2009). "Evidence for a Change in the Nuclear Mass Surface with the Discovery of the Most Neutron-Rich Nuclei with 17 ≤ Z ≤ 25". Physical Review Letters. 102 (14): 142501. arXiv:0903.1975. Bibcode:2009PhRvL.102n2501T. doi:10.1103/PhysRevLett.102.142501. PMID 19392430. S2CID 42329617. Retrieved 29 January 2023.
^ Ohnishi, Tetsuya; et al. (July 2010). "Identification of 45 New Neutron-Rich Isotopes Produced by In-Flight Fission of a 238U Beam at 345 MeV/nucleon". Journal of the Physical Society of Japan. 79 (7): 073201. arXiv:1006.0305. Bibcode:2010JPSJ...79g3201T. doi:10.1143/JPSJ.79.073201. S2CID 117037614. Retrieved 29 January 2023.
^ Tarasov, O. B.; et al. (May 2013). "Production cross sections from 82 Se fragmentation as indications of shell effects in neutron-rich isotopes close to the drip-line". Physical Review C. 87 (5): 054612. arXiv:1303.7164. Bibcode:2013PhRvC..87e4612T. doi:10.1103/PhysRevC.87.054612. S2CID 41501572. Retrieved 29 January 2023.
^ T. Sumikama; et al. (May 2017). "Observation of new neutron-rich Mn, Fe, Co, Ni, and Cu isotopes in the vicinity of 78 Ni". Physical Review C. 95 (5): 051601. Bibcode:2017PhRvC..95e1601S. doi:10.1103/PhysRevC.95.051601. hdl:10261/161832. Retrieved 29 January 2023.

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.

EC:	Electron capture
IT:	Isomeric transition
n:	Neutron emission
p:	Proton emission