Manganese (Mn)

Manganese (symbol Mn) is the chemical element with atomic number 25: a transition metal, solid at 0 °C, with an atomic mass of 54.938 u. Discovered in 1774 (Johan Gottlieb Gahn).

Manganese is a hard, brittle metal, more than 90% of which goes into steelmaking, where it removes sulfur and oxygen and strengthens the steel. In plants, a tiny cluster of manganese atoms performs a remarkable feat: splitting water molecules to release the oxygen we breathe. The ocean floor is strewn with manganese-rich nodules coveted by the mining industry.

Key facts

Atomic number: 25
Symbol: Mn
French name: Manganèse
Atomic mass: 54.938 u
Molar mass: 54.938 g/mol
Family: Transition metals
Position: period 4, group 7, d-block
State at 0 °C: Solid
Melting point: 1,245.9 °C
Boiling point: 2,060.9 °C
Density: 7.21 g/cm³
Electronegativity (Pauling): 1.55
First ionization energy: 717 kJ/mol
Atomic radius: 140 pm
Electron configuration: [Ar] 3d⁵ 4s²
Abundance in Earth's crust: 950 ppm (12th most abundant element)
Indicative price: 2 $/kg (order of magnitude)
Radioactive: no
Discovery: 1774, Johan Gottlieb Gahn

Origin of the name

From the Latin magnes, magnet, via “black magnesia.”

What does manganese look like?

A silvery-gray metal, very hard and brittle, that tarnishes slightly in air.

Where is manganese found?

About 0.1% of Earth's crust, the twelfth most abundant element. It is found in ancient sedimentary deposits and in the polymetallic nodules that carpet parts of the seafloor.

Natural sources

Pyrolusite
Rhodochrosite
Braunite
Psilomelane
Polymetallic nodules

How is manganese produced?

The ore is smelted with coke and iron in an electric furnace to produce ferromanganese, which is added to steel. About 20 million tonnes of contained manganese are produced each year. Pure manganese is obtained by electrolysis.

Top producers

South Africa
Gabon
Australia
China

What is manganese used for?

Steelmaking: deoxidizing and strengthening steel.
Aluminium alloy for drink cans.
Alkaline batteries (manganese dioxide) and lithium-ion batteries.
Potassium permanganate, a disinfectant and oxidizer.
Fertilizers and livestock supplements.

In everyday life

AA alkaline batteries
Railroad rails (manganese steel)
A drink can
Permanganate in the first-aid kit

Role in living things

Essential: it activates many enzymes, including a superoxide dismutase that protects the mitochondria. In photosynthesis, a cluster of four manganese atoms and one calcium atom oxidizes water and produces all the oxygen in the atmosphere.

Hazards of manganese

Long-term inhalation of dust or fumes (miners, welders) can cause manganism, a neurological disorder resembling Parkinson's disease. Taken in through food, it is of low toxicity.

Cosmic origin

White dwarfs: Produced by the thermonuclear explosion of a white dwarf (type Ia supernova).
Supernovae: Forged in the cores of massive stars, then scattered when they explode.

History of manganese

Manganese dioxide was used as a black pigment as far back as prehistory. In 1774, Carl Wilhelm Scheele recognized that it contained a new element, and his friend Johan Gottlieb Gahn isolated it the same year. Like magnesium, its name derives from the Greek region of Magnesia, which led to long confusion between the two.

Did you know?

Some black pigments in prehistoric caves, such as Lascaux, are manganese oxides.
In 1974, the CIA passed off the Hughes Glomar Explorer as a ship for mining manganese nodules, when its real mission was to recover a sunken Soviet submarine.
Old glass containing manganese turns violet after years in the sun.

Isotopes of manganese

A single stable isotope, manganese-55. Very long-lived manganese-53 is a clock for the formation of the Solar System's first bodies.

manganese-53: radioactive, half-life 3.7 × 10⁶ years. Chronometer of meteorite formation and a cosmogenic tracer.
manganese-54: radioactive, half-life 312 days. Calibration source for gamma detectors; an activation product in reactors.
manganese-55: 100% of natural manganese, stable

Related elements

Same family (transition metals): Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Yttrium (Y), Zirconium (Zr), Niobium (Nb), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Silver (Ag), Cadmium (Cd), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt), Gold (Au), Mercury (Hg), Rutherfordium (Rf), Dubnium (Db), Seaborgium (Sg), Bohrium (Bh), Hassium (Hs).

Same column (group 7): Technetium (Tc), Rhenium (Re), Bohrium (Bh).