Manganese(II) oxide that the Mn ions form a face centered cubic magnetic sub-lattice where there are ferromagnetically coupled sheets that are anti-parallel with adjacent sheets. Manganese(II) oxide undergoes the chemical reactions typical of an ionic oxide. Upon treatment with acids, it converts to the corresponding manganese(II) salt and water. Oxidation of manganese(II) oxide gives manganese(III) oxide. MnO occurs in nature as the rare mineral manganosite. Commercially it is prepared by reduction of MnO with hydrogen, carbon monoxide or methane, e.g.: MnO can also be prepared by decarbonation of the carbonate: This calcining process is conducted anaerobically, lest MnO form. An alternative route,
Manganese exists with a high spin, S = 5/2 ground state because of the high pairing energy for manganese(II). However, there are a few examples of low-spin, S =1/2 manganese(II). There are no spin-allowed d–d transitions in manganese(II), explaining why manganese(II) compounds are typically pale to colorless. The +3 oxidation state is known in compounds like manganese(III) acetate, but these are quite powerful oxidizing agents and also prone to disproportionation in solution, forming manganese(II) and manganese(IV). Solid compounds of manganese(III) are characterized by its strong purple-red color and a preference for distorted octahedral coordination resulting from the Jahn-Teller effect. The oxidation