manganese

Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery-gray metal and a transition element. In nature it is not found free but occurs mainly in minerals as oxides, carbonates, and silicates. The principal ore is pyrolusite (MnO2); other important sources include psilomelane, rhodochrosite (MnCO3), and various Mn-bearing silicates. Most refined manganese is used to produce alloys for steel and other metals.

In steelmaking, manganese serves as an essential alloying element, improving strength, toughness, and hardenability, and helping to deoxidize and desulfurize iron. It is commonly supplied in ferromanganese and silicomanganese alloys. Manganese oxides are also used in batteries (notably MnO2 as a cathode material in alkaline and some lithium-ion chemistries) and in catalysts, glass, pigments, and ceramics.

Manganese exhibits multiple oxidation states, most commonly +2, +3, +4, and +7 (as permanganate, MnO4−). The element is the essential trace nutrient manganese for humans and many organisms, acting as a cofactor for several enzymes involved in metabolism, bone formation, and antioxidant defense. Excessive exposure to manganese fumes or dust can cause neurotoxic effects known as manganism.

Global production centers include China, Gabon, Australia, and India. The element is the 12th most abundant in Earth’s crust, at about 0.1% by weight. Manganese thus plays a dual role as a vital industrial material and a potential environmental and health concern.