Manganese(III) oxide a structure related to the spinel structure of MnO where the oxide ions are cubic close packed. This is similar to the relationship between γ-FeO and FeO. γ-MnO is ferrimagnetic with a Néel temperature of 39 K. Manganese(III) oxide Manganese(III) oxide is a chemical compound with the formula MnO. Heating MnO in air at below 800 °C produces α-MnO (higher temperatures produce MnO). γ-MnO can be produced by oxidation followed by dehydration of manganese(II) hydroxide. Many preparations of nano-crystalline MnO have been reported, for example syntheses involving oxidation of Mn salts or reduction of MnO. Manganese (III) oxide is formed
Manganese dioxide silver or barium. is often called Hollandite, after a closely related mineral. Naturally occurring manganese dioxide contains impurities and a considerable amount of manganese(III) oxide. Only a limited number of deposits contain the γ modification in purity sufficient for the battery industry. Production of batteries and ferrite (two of the primary uses of manganese dioxide) requires high purity manganese dioxide. Batteries require "electrolytic manganese dioxide" while ferrites require "chemical manganese dioxide". One method starts with natural manganese dioxide and converts it using dinitrogen tetroxide and water to a manganese(II) nitrate solution. Evaporation of the water, leaves the crystalline nitrate salt.