manganese manganez (#) Fr.: manganèse Metallic chemical element; symbol Mn. Atomic number 25; atomic weight 54.938; melting point about 1,244°C; boiling point about 1,962°C. The name derives from the Latin magnes for "magnet" since pyrolusite (MnO2) has magnetic properties. It was discovered by the Swedish pharmacist and chemist Carl-Wilhelm Scheele in 1774. Manganez, loan from Fr. |