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Manganese


Manganese was discovered by Johann Gahn (1745 – 1818), a Swedish chemist. Manganese: Manganese is alloyed with steel to increase strength, hardness, and wear resistance. Manganese was recognized as a distinct substance by Carl Wilhelm Scheele, Torbern Olof Bergman, and others. It was isolated in 1774 by Johan Gahn by reducing the dioxide with carbon. Manganese is a gray-white metal that resembles iron but is harder and very brittle. It is chemically reactive and slowly decomposes in cold water. The pure metal exists in four allotropic forms. The alpha form is stable at ordinary temperatures. The gamma form changes to the alpha form at ordinary temperatures.



Name Manganese
Atomic Number 25
Atomic Weight 54.93805
Symbol Mn
Melting Point ( °C ) 1245.0 °C (1518.15 K, 2273.0 °F)
Boiling Point ( °C ) 1962.0 °C (2235.15 K, 3563.6 °F)
Density (g/cm3) @ 293 K: 7.43 g/cm3
Earth crust (%)
Discovery (Year) 1774
Group
Electron configuration
Ionization energy (eV)