Isotopes of manganese

Isotopes of manganese (₂₅Mn)
β−	54Fe
β+	54Cr
Standard atomic weight Ar°(Mn)
	54.938043±0.000002; 54.938±0.001 (abridged);
	view; talk; edit;

Naturally occurring manganese (₂₅Mn) is composed of one stable isotope, ⁵⁵Mn. Twenty-seven 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 seven 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 from ⁴⁶Mn to ⁷³Mn. 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]}	Isotopic abundance
Nuclide ^{[n 1]}	Excitation energy^{[n 7]}			Half-life	Decay mode ^{[n 4]}	Daughter isotope ^{[n 5]}	Spin and parity ^{[n 6]}^{[n 7]}	Isotopic abundance
⁴⁶Mn	25	21	45.986669(93)	36.2(4) ms	β⁺, p (57.0%)	⁴⁵V	(4+)
					β⁺ (25%)	⁴⁶Cr
					β⁺, 2p (18%)	⁴⁴Ti
					β⁺, α?	⁴²Ti
⁴⁷Mn	25	22	46.975774(34)	88.0(13) ms	β⁺	⁴⁷Cr	5/2−#
⁴⁷Mn	25	22	46.975774(34)	88.0(13) ms	β⁺, p? (<1.7%)	⁴⁶V	5/2−#
⁴⁸Mn	25	23	47.9685488(72)	158.1(22) ms	β⁺ (99.72%)	⁴⁸Cr	4+
					β⁺, p (0.28%)	⁴⁷V
					β⁺, α (6×10⁻⁴%)	⁴⁴Ti
⁴⁹Mn	25	24	48.9596134(24)	382(7) ms	β⁺	⁴⁹Cr	5/2−
⁵⁰Mn	25	25	49.95423816(12)	283.21(7) ms	β⁺	⁵⁰Cr	0+
^50mMn	225.31(7) keV			1.75(3) min	β⁺	⁵⁰Cr	5+
⁵¹Mn	25	26	50.94820877(33)	45.81(21) min	β⁺	⁵¹Cr	5/2−
⁵²Mn	25	27	51.94555909(14)	5.591(3) d	β⁺	⁵²Cr	6+
^52mMn	377.749(5) keV			21.1(2) min	β⁺ (98.22%)	⁵²Cr	2+
^52mMn	377.749(5) keV			21.1(2) min	IT (1.78%)	⁵²Mn	2+
⁵³Mn	25	28	52.94128750(37)	3.7(4)×10⁶ y	EC	⁵³Cr	7/2−	trace
⁵⁴Mn	25	29	53.9403558(11)	312.081(32) d	EC	⁵⁴Cr	3+
					β⁻ (9.3×10⁻⁵%)	⁵⁴Fe
					β⁺ (1.28×10⁻⁷%)	⁵⁴Cr
⁵⁵Mn	25	30	54.93804304(28)	Stable			5/2−	1.0000
⁵⁶Mn	25	31	55.93890282(31)	2.5789(1) h	β⁻	⁵⁶Fe	3+
⁵⁷Mn	25	32	56.9382859(16)	85.4(18) s	β⁻	⁵⁷Fe	5/2−
⁵⁸Mn	25	33	57.9400666(29)	3.0(1) s	β⁻	⁵⁸Fe	1+
^58mMn	71.77(5) keV			65.4(5) s	β⁻	⁵⁸Fe	4+
^58mMn	71.77(5) keV			65.4(5) s	IT?	⁵⁸Mn	4+
⁵⁹Mn	25	34	58.9403911(25)	4.59(5) s	β⁻	⁵⁹Fe	5/2−
⁶⁰Mn	25	35	59.9431366(25)	280(20) ms	β⁻	⁶⁰Fe	1+
^60mMn	271.90(10) keV			1.77(2) s	β⁻ (88.5%)	⁶⁰Fe	4+
^60mMn	271.90(10) keV			1.77(2) s	IT (11.5%)	⁶⁰Mn	4+
⁶¹Mn	25	36	60.9444525(25)	709(8) ms	β⁻	⁶¹Fe	5/2−
⁶¹Mn	25	36	60.9444525(25)	709(8) ms	β⁻, n?	⁶⁰Fe	5/2−
⁶²Mn	25	37	61.9479074(70)	92(13) ms	β⁻	⁶²Fe	1+
⁶²Mn	25	37	61.9479074(70)	92(13) ms	β⁻, n?	⁶¹Fe	1+
^62mMn^{[n 8]}	343(6) keV			671(5) ms	β⁻	⁶²Fe	4+
					β⁻, n?	⁶¹Fe
					IT?	⁶¹Mn
⁶³Mn	25	38	62.9496647(40)	275(4) ms	β⁻	⁶³Fe	5/2−
⁶³Mn	25	38	62.9496647(40)	275(4) ms	β⁻, n?	⁶²Fe	5/2−
⁶⁴Mn	25	39	63.9538494(38)	88.8(24) ms	β⁻ (97.3%)	⁶⁴Fe	1+
⁶⁴Mn	25	39	63.9538494(38)	88.8(24) ms	β⁻, n (2.7%)	⁶³Fe	1+
^64mMn	174.1(5) keV			439(31) μs	IT	⁶⁴Mn	(4+)
⁶⁵Mn	25	40	64.9560197(40)	91.9(7) ms	β⁻ (92.1%)	⁶⁵Fe	(5/2−)
⁶⁵Mn	25	40	64.9560197(40)	91.9(7) ms	β⁻, n (7.9%)	⁶⁴Fe	(5/2−)
⁶⁶Mn	25	41	65.960547(12)	63.8(9) ms	β⁻ (92.6%)	⁶⁶Fe	(1+)
					β⁻, n (7.4%)	⁶⁵Fe
					β⁻, 2n?	⁶⁴Fe
^66mMn	464.5(4) keV			780(40) μs	IT	⁶⁶Mn	(5−)
^66mMn	464.5(4) keV			780(40) μs	β⁻?	⁶⁶Fe	(5−)
⁶⁷Mn	25	42	66.96395(22)#	46.7(23) ms	β⁻ (90%)	⁶⁷Fe	5/2−#
					β⁻, n (10%)	⁶⁶Fe
					β⁻, 2n?	⁶⁵Fe
⁶⁸Mn	25	43	67.96895(32)#	33.7(15) ms	β⁻ (82%)	⁶⁸Fe	(3)
					β⁻, n (18%)	⁶⁷Fe
					β⁻, 2n?	⁶⁶Fe
⁶⁹Mn	25	44	68.97278(43)#	22.1(16) ms	β⁻ (60%)	⁶⁹Fe	5/2−#
					β⁻, n (40%)	⁶⁸Fe
					β⁻, 2n?	⁶⁷Fe
⁷⁰Mn	25	45	69.97805(54)#	19.9(17) ms	β⁻	⁷⁰Fe	(4,5)
					β⁻, n?	⁶⁹Fe
					β⁻, 2n?	⁶⁸Fe
⁷¹Mn	25	46	70.98216(54)#	16# ms [>400 ns]	β⁻?	⁷¹Fe	5/2-#
					β⁻, n?	⁷⁰Fe
					β⁻, 2n?	⁶⁹Fe
⁷²Mn	25	47	71.98801(64)#	12# ms [>620 ns]	β⁻?	⁷²Fe
					β⁻, n?	⁷¹Fe
					β⁻, 2n?	⁷⁰Fe
⁷³Mn	25	48	72.99281(64)#	12# ms [>410 ns]	β⁻?	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).
^ Order of ground state and isomer is uncertain.

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.