SPECTRUM
Chemical Fact Sheet
Manganese
 
Chemical Abstract Number (CAS #) 7439-96-5
Analytical Methods 200.7 - 200.8 - 6010 - 6020
Atomic Symbol Mn
Synopsis from the CRC Handbook of Chemistry and Physics 92nd Edition 2011-2013

Manganese — (L. magnes, magnet, from magnetic properties of pyrolusite; It. manganese, corrupt form of magnesia), Mn; at. wt. 54.938045(5); at. no. 25; m.p. 1246 °C; b.p. 2061 °C; sp. gr. 7.21 to 7.44, depending on allotropic form; valence 1, 2, 3, 4, 6, or 7. Recognized by Scheele, Bergman, and others as an element and isolated by Gahn in 1774 by reduction of the dioxide with carbon. Manganese minerals are widely distributed; oxides, silicates, and carbonates are the most common. The discovery of large quantities of manganese nodules on the floor of the oceans holds promise as a source of manganese. These nodules contain about 24% manganese together with many other elements in lesser abundance. Most manganese today is obtained from ores found in Ukraine, Brazil, Australia, Republic of So. Africa, Gabon, China, and India. Pyrolusite (MnO2) and rhodochrosite (MnCO3) are among the most common manganese minerals. The metal is obtained by reduction of the oxide with sodium, magnesium, aluminum, or by electrolysis. It is gray-white, resembling iron, but is harder and very brittle. The metal is reactive chemically, and decomposes in cold water slowly. Manganese is used to form many important alloys. In steel, manganese improves the rolling and forging qualities, strength, toughness, stiffness, wear resistance, hardness, and hardenability. With aluminum and antimony, especially with small amounts of copper, it forms highly ferromagnetic alloys. Manganese metal is ferromagnetic only after special treatment. The pure metal exists in four allotropic forms. The alpha form is stable at ordinary temperature; gamma manganese, which changes to alpha at ordinary temperatures, is soft, easily cut, and capable of being bent. The dioxide (pyrolusite) is used as a depolarizer in dry cells, and is used to “decolorize” glass that is colored green by impurities of iron. Manganese by itself colors glass an amethyst color, and is responsible for the color of true amethyst. The dioxide is also used in the preparation of oxygen and chlorine, and in drying black paints. The permanganate is a powerful oxidizing agent and is used in quantitative analysis and in medicine. Manganese is widely distributed throughout the animal kingdom. It is an important trace element and may be essential for The Elements 4-21 utilization of vitamin B1. Twenty-seven isotopes and isomers are known. Manganese metal (99.95%) is priced at about $800/ kg. Metal of 99.6% purity is priced at about $80/kg.
Molecular Weight
54.938
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