1. A gray-white or silvery brittle metallic element, occurring in several allotropic forms, found worldwide, especially in the ores pyrolusite and rhodochrosite and in nodules on the ocean floor. it is alloyed with steel to increase strength, hardness, wear resistance, and other properties and with other metals to form highly ferromagnetic materials. atomic number 25; atomic weight 54.9380; melting point 1,244°C; boiling point 1,962°C; specific gravity 7.21 to 7.44; valence 1, 2, 3, 4, 6, 7. see table at element.

1. A metallic chemical element (symbol Mn) with an atomic number of 25.

1. an element obtained by reduction of its oxide, as a hard, grayish white metal, fusible with difficulty (melting point 1244° C), but easily oxidized. its ores occur abundantly in nature as the minerals pyrolusite, manganite, etc. symbol Mn. atomic number 25; atomic weight 54.938 [C=12.011].

1. chemical symbol, Mn; atomic weight, 55. A metal having a remarkable affinity for, and in some respects a close resemblance to, iron, of which it is an extremely frequent associate.

1. a hard brittle grey polyvalent metallic element that resembles iron but is not magnetic; used in making steel; occurs in many minerals