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 combination
with iron, and in many minerals.
Manganese is a metal with important industrial metal alloy uses,
particularly in stainless steels.
Historically, manganese is
named for various black minerals (such as pyrolusite)
from the same region of Magnesia in Greece which gave names to
similar-sounding magnesium, Mg,
and magnetite, an
ore of the element iron, Fe. By the mid-18th century,Swedish 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, by reducing the dioxide with carbon.
Manganese
phosphating is used
as a treatment for rust and corrosion prevention on steel. Depending on their oxidation state,
manganese ions have
various colors and are used industrially as pigments. 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.[2] 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. The
element is a required trace mineral for all known living organisms but is a neurotoxin. In
larger amounts, and apparently with far greater effectiveness through
inhalation, it can cause a poisoning syndrome in mammals, with neurological damage which
is sometimes irreversible.
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