Manganese is a chemical element that has the symbol Mn and atomic number 25. It is found as the free element in nature (often in combination with iron), and in many minerals. The free element is a metal with important industrial metal alloy uses. Manganese ions are variously colored, and are used industrially as pigments and as oxidants. Manganese (II) ions function as cofactors for a number of enzymes and the element is thus an essential trace mineral for all known living organisms.