Manganese
Element 25 · Transition Metal
Manganese is a hard, brittle, silvery transition metal with the widest range of common oxidation states of any period-4 element, from +2 to +7 — each with a distinct color, from pale pink to deep purple. Discovered in 1774, it became indispensable to the steel industry, where it removes oxygen and sulfur impurities and greatly increases hardness.
Biologically, manganese is an essential trace nutrient used in enzymes for metabolism and antioxidant defense, though inhaling large amounts of its dust can harm the nervous system. The purple of potassium permanganate solutions is one of chemistry's most recognizable sights.
Key facts
| Atomic number | 25 |
|---|---|
| Atomic weight | 54.938 |
| Category | Transition Metal |
| Group / Period | 7 / 4 |
| Block | d |
| Electron configuration | [Ar] 3d5 4s2 |
| Common oxidation states | +7, +4, +3, +2 |
| State at STP | Solid |
| Electronegativity | 1.55 |
| Atomic radius | 161 pm |
| Density | 7.21 g/cm³ |
| Melting point | 1246 °C |
| Boiling point | 2061 °C |
Occurrence
Manganese is the twelfth most abundant element in Earth's crust, mined mainly as the mineral pyrolusite (manganese dioxide). Vast reserves also lie in manganese nodules scattered across the deep ocean floor. It never occurs as a free metal because it oxidizes readily.
Applications
Steelmaking consumes most manganese as ferromanganese to harden and deoxidize steel
Dry-cell and alkaline batteries use manganese dioxide as the cathode material
Pigments and ceramic colorants employ manganese compounds
Water treatment plants use potassium permanganate to remove iron and odors
Trace manganese in fertilizers supports plant enzyme function
Common compounds
- manganese dioxide
- potassium permanganate
- manganese sulfate
- manganese carbonate
Cave paintings at Lascaux were drawn with manganese dioxide black pigment over 17,000 years ago.
Data source: IUPAC standard atomic weights 2021