Naturally occurring manganese (25Mn) is composed of 1 stable isotope, 55Mn. 25 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 1 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 states.
Manganese is part of the iron group of elements, which are thought to be synthesized in large stars shortly before supernova explosion. 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. 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 65 u (65Mn). The primary decay mode before the most abundant stable isotope, 55Mn, is electron capture and the primary mode after is beta decay.
|Main isotopes of manganese (25Mn)|
|Standard atomic weight Ar, standard(Mn)|
isotopic mass (u)
|range of natural|
|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−#|
|β+, p (3.4%)||46V|
|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|
|50mMn||229(7) keV||1.75(3) min||β+||50Cr||5+|
|52mMn||377.749(5) keV||21.1(2) min||β+ (98.25%)||52Cr||2+|
|54Mn||25||29||53.9403589(14)||312.03(3) d||EC 99.99%||54Cr||3+|
|58mMn||71.78(5) keV||65.2(5) s||β− (>99.9%)||58Fe||(4)+|
|60mMn||271.90(10) keV||1.77(2) s||β− (88.5%)||60Fe||3+|
|62Mn||25||37||61.94843(24)||671(5) ms||β− (>99.9%)||62Fe||(3+)|
|β−, n (<.1%)||61Fe|
|62mMn||0(150)# keV||92(13) ms||(1+)|
|64Mn||25||39||63.95425(29)||88.8(25) ms||β− (>99.9%)||64Fe||(1+)|
|β−, n (<.1%)||63Fe|
|64mMn||135(3) keV||>100 µs|
|65Mn||25||40||64.95634(58)||92(1) ms||β− (>99.9%)||65Fe||5/2−#|
|β−, n (<.1%)||64Fe|
|66Mn||25||41||65.96108(43)#||64.4(18) ms||β− (>99.9%)||66Fe|
|β−, n (<.1%)||65Fe|
Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in minerals in combination with iron. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels.
Historically, manganese is named for pyrolusite and other black minerals from the region of Magnesia in Greece, which also gave its name to magnesium and the iron ore magnetite. By the mid-18th century, Swedish-German chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite (now known to be manganese dioxide) contained a new element, but they were unable to isolate it. Johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon.
Manganese phosphating is used for rust and corrosion prevention on steel. Ionized manganese is used industrially as pigments of various colors, which depend on the oxidation state of the ions. The permanganates of alkali and alkaline earth metals are powerful oxidizers. Manganese dioxide is used as the cathode (electron acceptor) material in zinc-carbon and alkaline batteries.
In biology, manganese(II) ions function as cofactors for a large variety of enzymes with many functions. Manganese enzymes are particularly essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the oxygen-evolving complex of photosynthetic plants. While the element is a required trace mineral for all known living organisms, it also acts as a neurotoxin in larger amounts. Especially through inhalation, it can cause manganism, a condition in mammals leading to neurological damage that is sometimes irreversible.Manganese (disambiguation)
Manganese is a chemical element with symbol Mn and atomic number 25.
Manganese may also refer to:
Manganese, Minnesota, a ghost town
Manganese, West Virginia
SS Manganese, a steamship