Isotopes of manganese

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 312.08 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.

Isotopes of manganese (₂₅Mn)

Main isotopes[1] Decay abun­dance half-life (t1/2) 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 Ar°(Mn)
	54.938043±0.000002[2] 54.938±0.001 (abridged)[3]
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Manganese is part of the iron group of elements, which are thought to be synthesized in massive stars shortly before supernova explosions. Because of its relatively short half-life, ⁵³Mn occurs on Earth only in tiny amounts due to the action of cosmic rays on iron in rocks.^[4] As ⁵³Mn decays to ⁵³Cr, manganese isotopic analysis is typically combined with that of chromium and this has 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 shortly 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
	Excitation energy[n 7]
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−#
					β+, p? (<1.7%)	46V
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+
					IT (1.78%)	52Mn
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+
					IT?	58Mn
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+
					IT (11.5%)	60Mn
61Mn	25	36	60.9444525(25)	709(8) ms	β−	61Fe	5/2−
					β−, n?	60Fe
62Mn	25	37	61.9479074(70)	92(13) ms	β−	62Fe	1+
					β−, n?	61Fe
62mMn[n 8]	343(6) keV			671(5) ms	β−	62Fe	4+
					β−, n?	61Fe
					IT?	62Mn
63Mn	25	38	62.9496647(40)	275(4) ms	β−	63Fe	5/2−
					β−, n?	62Fe
64Mn	25	39	63.9538494(38)	88.8(24) ms	β− (97.3%)	64Fe	1+
					β−, n (2.7%)	63Fe
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−)
					β−, n (7.9%)	64Fe
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−)
					β−?	66Fe
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

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

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

5. Bold symbol as daughter – Daughter product is stable.
6. ( ) spin value – Indicates spin with weak assignment arguments.
7. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
8. Order of ground state and isomer is uncertain.

See also

Daughter products other than manganese

• Isotopes of iron
• Isotopes of chromium
• Isotopes of vanadium
• Isotopes of titanium