Manganese(II,III) oxide a weighting agent while drilling reservoir sections in oil and gas wells. Manganese(II,III) oxide Manganese(II,III) oxide is the chemical compound with formula MnO. Manganese is present in two oxidation states +2 and +3 and the formula is sometimes written as MnO.MnO. MnO is found in nature as the mineral hausmannite. MnO formed when any manganese oxide is heated in air above 1000 °C. Considerable research has centred on producing nanocrystalline MnO and various syntheses that involve oxidation of Mn or reduction of Mn. MnO has been found to act as a catalyst for a range of reactions e.g. the oxidation
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.