Manganese (Mn)
“The great shape-shifter of the periodic table — manganese shows more oxidation states than any other element, from pale pink Mn²⁺ to deep purple MnO₄⁻.”
How its electrons are arranged
Computed from the aufbau principle, with known real-world exceptions applied automatically.
Characteristics
- Configuration [Ar] 3d⁵ 4s² — a half-filled 3d subshell of exactly five electrons, an arrangement of special stability; manganese sits in Period 4, Group 7, of the d-block.
- Champion of oxidation states: they run from +2 (the pale pink Mn²⁺ ion) through +4 (the black MnO₂ of batteries) up to +7 (the deep purple permanganate, MnO₄⁻, one of the strongest oxidising agents in the school laboratory).
- Hard and brittle, far more so than iron — yet small additions of manganese make steel dramatically tougher, which is why nearly nine-tenths of all manganese mined goes into steel.
- Essential to every breath you take: the water-splitting machinery at the heart of photosynthesis is a cluster of four manganese atoms and one calcium atom — the sole source of Earth’s oxygen. Over-exposure, however, causes the Parkinson-like “manganism” among miners.
A hard, brittle, grey-white metal that looks much like iron but is paler and far less forgiving — hit it and it shatters rather than bends. It tarnishes slowly in moist air and usually reaches the market as silvery little lumps or a dark grey powder.
Where you meet it
✦ Uses
- Hardening steel for railways — rail tracks, including the metro-rail line through Dhaka, carry about 1% manganese, and crossings use 12–14% manganese steel that actually grows harder the more trains hammer it.
- Dry-cell batteries — the black manganese dioxide (MnO₂) paste inside a torch or remote-control battery soaks up the hydrogen gas that would otherwise kill the cell.
- Potassium permanganate (KMnO₄) — those near-black purple crystals, dissolved in water, disinfect drinking water, wash fish and prawns, and clean wounds in village homes and fish farms across Bangladesh.
- Strengthening aluminium — drink cans and cooking pots made of aluminium-manganese alloy resist dents and corrosion far better than pure aluminium.
◍ Everyday examples
- The steel rails a train thunders over — every length of track carries a sprinkling of manganese for toughness.
- A pinch of permanganate turning a bucket of village water pale violet before the day’s fish or vegetables are washed.
- A plate of lentils, rice and green vegetables carrying the few milligrams of manganese your body needs each day for strong bones and a healthy brain.
History & name
Glassmakers had known for centuries that a certain black mineral, pyrolusite (MnO₂), could wash the green tint out of glass and leave it crystal clear, yet nobody knew what hid inside the black stone. In the early 1770s the Swedish chemist Carl Wilhelm Scheele showed that pyrolusite contained a new metal, and in 1774 his friend, the mineralogist Johan Gottlieb Gahn, sealed pyrolusite with charcoal in a crucible and heated it fiercely — out came a lump of a metal never before seen pure. The old mineral names were a tangle: the Romans had called the black ore magnes after the magnet, confusing it with black magnetic iron ore, and alchemists separated magnesia nigra (“black magnesia”) from the white magnesia of magnesium. From this corrupted glassmakers’ word manganesum the new metal took its name: manganese.