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 until 2000, the only United States coin to use manganese was the from 1942 to 1945. An alloy of 75% copper and 25% nickel was traditionally used for the production of nickel coins. However, because of shortage of nickel metal during the war, it was substituted by more available silver and manganese, thus resulting in an alloy of 56% copper, 35% silver and 9% manganese. Since 2000, dollar coins, for example the Sacagawea dollar and the Presidential $1 coins, are made from a brass containing 7% of manganese with a pure copper core. In both cases of nickel and dollar,