Manganese was first recognized as an element in 1774 by Carl Wilhelm Scheele while working with the mineral pyrolusite, and was isolated the same year by his associate, Johan Gottlieb Gahn.
Manganese oxide is the most important manganese compound. Pyrolusite is the chief source of manganese and all its compounds, when derived from ores. Pyrolusite is widely used as a chemical oxidant in organic synthesis. Manganese oxide is also used as the cathode material in electric dry cells. Synthetic manganese oxide is prepared by decomposition of manganese nitrate; by reaction of manganese sulfate, oxygen and sodium hydroxide; or by electrolysis of an aqueous solution of manganese sulfate.