Manganese (pronounced) is a chemical element that is designated by the symbol Mn and has an atomic number of 25. It is found as the free element in nature (often in combination with iron), and in many minerals. The free element is a metal with important industrial metal alloy uses. Manganese ions are variously colored, and are used industrially as pigments and as oxidation chemicals. Manganese (II) ions function as cofactors for a number of enzymes; the element is thus a required trace mineral for all known living organisms.
Manganese is essential to iron and steel production by virtue of its sulfur-fixing, deoxidizing, and alloying properties. Steel making, including its iron making component, has accounted for most manganese demand, presently in the range of 85% to 90% of the total demand. Among a variety of other uses, manganese is a key component of low-cost stainless steel formulations and certain widely used aluminum alloys.
Manganese compounds were in use in prehistoric times; paints that were pigmented with manganese dioxide can be traced back 17,000 years. The Egyptians and Romans used manganese compounds in glass-making, to either remove color from glass or add color to it. Manganese can be found in the iron ores used by the Spartans. Some speculate that the exceptional hardness of Spartan steels derives from the inadvertent production of an iron-manganese alloy.
High Carbon Silico Manganese
The origin of the name manganese is complex. In ancient times, two black minerals from magnesia in what is now modern greece were both called magnes, but were thought to differ in gender. The male magnes attracted iron, and was the iron ore we now know as loadstone or magnetite, and which probably gave us the term magnet. The female magnes ore did not attract iron, but was used to decolorize glass. This feminine magnes was later called magnesia, known now in modern times as pyrolusite or manganese dioxide. This mineral is never magnetic (although manganese itself is paramagnetic).
The classes of enzymes that have manganese cofactors are very broad and include such classes as oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases, lectins, and integrins. The reverse transcriptases of many retroviruses (though not lentiviruses such as HIV) contain manganese. The best known manganese-containing polypeptides may be arginase, the diphtheria toxin, and Mn-containing super oxide dismutase (Mn-SOD).
: << 1