manganoxider

Manganoxider, or manganese oxides, are a group of inorganic compounds consisting of manganese and oxygen. They exhibit several oxidation states for manganese, primarily +2, +3, and +4 in the common binary oxides, and often occur as mixed-valence solids.

The principal binary oxides are MnO, MnO2, Mn2O3, and Mn3O4. In nature, MnO2 minerals such as pyrolusite are important ores; hydrated and layered forms, including birnessite, occur in soils and marine sediments.

Physical properties vary with structure and oxidation state. MnO is a pale-green solid; MnO2 is a black to brown insoluble solid; Mn2O3 is brownish; Mn3O4 is black. They crystallize in diverse structures, including rock-salt, rutile-like, and spinel-type frameworks.

Formation is largely through oxidation of Mn(II) minerals in weathering environments, but industrial oxidation and high-temperature processing can produce oxides directly from manganese-containing materials.

Applications include pigments, catalysts, and battery materials. MnO2 serves as a cathode material in zinc–carbon and alkaline batteries; mixed manganese oxides and LiMn2O4 are used in rechargeable lithium-ion batteries. In environmental contexts, Mn oxides mediate oxidation of contaminants.

Safety: manganese oxides are generally of low solubility; inhalation of dust can irritate the respiratory tract, and prolonged exposure may pose health risks. Appropriate protective measures are recommended in industrial settings.