Naturally occurring

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

(₂₅Mn) is composed of one stable

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

, ⁵⁵Mn. 25

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

s have been characterized, with the most stable being ⁵³Mn with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

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 Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...

isotopes have half-lives that are less than 3 hours and the majority of these have half-lives that are less than a minute, but only ⁴⁵Mn has an unknown half-life. The least stable is ⁴⁴Mn with a half-life shorter than 105 nanoseconds. This element also has 3

meta state A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ...

s. Manganese is part of the

iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

group of elements, which are thought to be synthesized in large stars shortly before supernova explosions. ⁵³Mn decays to ⁵³chromium, Cr with a

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

in rocks. 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 Aluminium-26, ²⁶Al and ¹⁰⁷Palladium, Pd 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 nucleosynthesis, nucleosynthetic processes immediately before coalescence of the Solar System. The isotopes of manganese range in atomic weight from 44 atomic mass unit, u (⁴⁴Mn) to 69 u (⁶⁹Mn). 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

, - , ⁴⁴Mn , style="text-align:right" , 25 , style="text-align:right" , 19 , 44.00687(54)# , <105 ns , proton emission, p , ⁴³Cr , (2−)# , , , - , ⁴⁵Mn , style="text-align:right" , 25 , style="text-align:right" , 20 , 44.99451(32)# , unknown , p , ⁴⁴Cr , (7/2−)# , , , - , rowspan=4, ⁴⁶Mn , rowspan=4 style="text-align:right" , 25 , rowspan=4 style="text-align:right" , 21 , rowspan=4, 45.98672(12)# , rowspan=4, 37(3) ms , beta decay, β⁺ (78%) , ⁴⁶Cr , rowspan=4, (4+) , rowspan=4, , rowspan=4, , - , β⁺, p (22%) , ⁴⁵V , - , β⁺, alpha decay, α (<1%) , ⁴²Ti , - , β⁺, 2p (<1%) , ⁴⁴Ti , - , style="text-indent:1em" , ^46mMn , colspan="3" style="text-indent:2em" , 150(100)# keV , 1# ms , β⁺ , ⁴⁶Cr , 1-# , , , - , rowspan=2, ⁴⁷Mn , rowspan=2 style="text-align:right" , 25 , rowspan=2 style="text-align:right" , 22 , rowspan=2, 46.97610(17)# , rowspan=2, 100(50) ms , β⁺ (96.6%) , ⁴⁷Cr , rowspan=2, 5/2−# , rowspan=2, , rowspan=2, , - , β⁺, p (3.4%) , ⁴⁶V , - , rowspan=3, ⁴⁸Mn , rowspan=3 style="text-align:right" , 25 , rowspan=3 style="text-align:right" , 23 , rowspan=3, 47.96852(12) , rowspan=3, 158.1(22) ms , β⁺ (99.71%) , ⁴⁸Cr , rowspan=3, 4+ , rowspan=3, , rowspan=3, , - , β⁺, p (.027%) , ⁴⁷V , - , β⁺, α (6×10⁻⁴%) , ⁴⁴Ti , - , ⁴⁹Mn , style="text-align:right" , 25 , style="text-align:right" , 24 , 48.959618(26) , 382(7) ms , β⁺ , ⁴⁹Cr , 5/2− , , , - , ⁵⁰Mn , style="text-align:right" , 25 , style="text-align:right" , 25 , 49.9542382(11) , 283.29(8) ms , β⁺ , ⁵⁰Cr , 0+ , , , - , style="text-indent:1em" , ^50mMn , colspan="3" style="text-indent:2em" , 229(7) keV , 1.75(3) min , β⁺ , ⁵⁰Cr , 5+ , , , - , ⁵¹Mn , style="text-align:right" , 25 , style="text-align:right" , 26 , 50.9482108(11) , 46.2(1) min , β⁺ , ⁵¹Cr , 5/2− , , , - , ⁵²Mn , style="text-align:right" , 25 , style="text-align:right" , 27 , 51.9455655(21) , 5.591(3) d , β⁺ , ⁵²Cr , 6+ , , , - , rowspan=2 style="text-indent:1em" , ^52mMn , rowspan=2 colspan="3" style="text-indent:2em" , 377.749(5) keV , rowspan=2, 21.1(2) min , β⁺ (98.25%) , ⁵²Cr , rowspan=2, 2+ , rowspan=2, , rowspan=2, , - , Isomeric transition, IT (1.75%) , ⁵²Mn , - , ⁵³Mn , style="text-align:right" , 25 , style="text-align:right" , 28 , 52.9412901(9) , 3.7(4)×10⁶ y , Electron capture, EC , ⁵³Cr , 7/2− , trace radioisotope, trace , , - , rowspan=3, ⁵⁴Mn , rowspan=3 style="text-align:right" , 25 , rowspan=3 style="text-align:right" , 29 , rowspan=3, 53.9403589(14) , rowspan=3, 312.03(3) d , EC 99.99% , ⁵⁴Cr , rowspan=3, 3+ , rowspan=3, , rowspan=3, , - , β⁻ (2.9×10⁻⁴%) , ⁵⁴Fe , - , β⁺ (5.76×10⁻⁷%) , ⁵⁴Cr , - , ⁵⁵Mn , style="text-align:right" , 25 , style="text-align:right" , 30 , 54.9380451(7) , colspan=3 align=center, Stable , 5/2− , 1.0000 , , - , ⁵⁶Mn , style="text-align:right" , 25 , style="text-align:right" , 31 , 55.9389049(7) , 2.5789(1) h , β⁻ , ⁵⁶Fe , 3+ , , , - , ⁵⁷Mn , style="text-align:right" , 25 , style="text-align:right" , 32 , 56.9382854(20) , 85.4(18) s , β⁻ , ⁵⁷Fe , 5/2− , , , - , ⁵⁸Mn , style="text-align:right" , 25 , style="text-align:right" , 33 , 57.93998(3) , 3.0(1) s , β⁻ , ⁵⁸Fe , 1+ , , , - , rowspan=2 style="text-indent:1em" , ^58mMn , rowspan=2 colspan="3" style="text-indent:2em" , 71.78(5) keV , rowspan=2, 65.2(5) s , β⁻ (>99.9%) , ⁵⁸Fe , rowspan=2, (4)+ , rowspan=2, , rowspan=2, , - , IT (<.1%) , ⁵⁸Mn , - , ⁵⁹Mn , style="text-align:right" , 25 , style="text-align:right" , 34 , 58.94044(3) , 4.59(5) s , β⁻ , ⁵⁹Fe , (5/2)− , , , - , ⁶⁰Mn , style="text-align:right" , 25 , style="text-align:right" , 35 , 59.94291(9) , 51(6) s , β⁻ , ⁶⁰Fe , 0+ , , , - , rowspan=2 style="text-indent:1em" , ^60mMn , rowspan=2 colspan="3" style="text-indent:2em" , 271.90(10) keV , rowspan=2, 1.77(2) s , β⁻ (88.5%) , ⁶⁰Fe , rowspan=2, 3+ , rowspan=2, , rowspan=2, , - , IT (11.5%) , ⁶⁰Mn , - , ⁶¹Mn , style="text-align:right" , 25 , style="text-align:right" , 36 , 60.94465(24) , 0.67(4) s , β⁻ , ⁶¹Fe , (5/2)− , , , - , rowspan=2, ⁶²Mn , rowspan=2 style="text-align:right" , 25 , rowspan=2 style="text-align:right" , 37 , rowspan=2, 61.94843(24) , rowspan=2, 671(5) ms , β⁻ (>99.9%) , ⁶²Fe , rowspan=2, (3+) , rowspan=2, , rowspan=2, , - , β⁻, neutron emission, n (<.1%) , ⁶¹Fe , - , style="text-indent:1em" , ^62mMn , colspan="3" style="text-indent:2em" , 0(150)# keV , 92(13) ms , , , (1+) , , , - , ⁶³Mn , style="text-align:right" , 25 , style="text-align:right" , 38 , 62.95024(28) , 275(4) ms , β⁻ , ⁶³Fe , 5/2−# , , , - , rowspan=2, ⁶⁴Mn , rowspan=2 style="text-align:right" , 25 , rowspan=2 style="text-align:right" , 39 , rowspan=2, 63.95425(29) , rowspan=2, 88.8(25) ms , β⁻ (>99.9%) , ⁶⁴Fe , rowspan=2, (1+) , rowspan=2, , rowspan=2, , - , β⁻, n (<.1%) , ⁶³Fe , - , style="text-indent:1em" , ^64mMn , colspan="3" style="text-indent:2em" , 135(3) keV , >100 µs , , , , , , - , rowspan=2, ⁶⁵Mn , rowspan=2 style="text-align:right" , 25 , rowspan=2 style="text-align:right" , 40 , rowspan=2, 64.95634(58) , rowspan=2, 92(1) ms , β⁻ (>99.9%) , ⁶⁵Fe , rowspan=2, 5/2−# , rowspan=2, , rowspan=2, , - , β⁻, n (<.1%) , ⁶⁴Fe , - , rowspan=2, ⁶⁶Mn , rowspan=2 style="text-align:right" , 25 , rowspan=2 style="text-align:right" , 41 , rowspan=2, 65.96108(43)# , rowspan=2, 64.4(18) ms , β⁻ (>99.9%) , ⁶⁶Fe , rowspan=2, , rowspan=2, , rowspan=2, , - , β⁻, n (<.1%) , ⁶⁵Fe , - , ⁶⁷Mn , style="text-align:right" , 25 , style="text-align:right" , 42 , 66.96414(54)# , 45(3) ms , β⁻ , ⁶⁷Fe , 5/2−# , , , - , ⁶⁸Mn , style="text-align:right" , 25 , style="text-align:right" , 43 , 67.96930(64)# , 28(4) ms , , , , , , - , ⁶⁹Mn , style="text-align:right" , 25 , style="text-align:right" , 44 , 68.97284(86)# , 14(4) ms , , , 5/2−# , ,

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Isotopes of manganese, Manganese Lists of isotopes by element, Manganese