Manganese metal is gray-white, resembling iron, but is harder and very brittle. The metal is reactive chemically, and decomposes cold water slowly. Manganese is widely distributed throughout the animal kingdom. It is an important trace element and may be essential for utilisation of vitamin B. Manganese is present in quantity the floor of oceans. It is an important component of steel.
Image adapted with permission fromProf James Marshall's (U. North Texas, USA)Walking Tour of the elements CD.
Manganese compounds are essential to life. They are essential for the action of some enzymes. Soil deficiencies lead to infertility in mammals and to bone malformation in growing chicks.
Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of manganese where known.
Manganese wasdiscovered by Johann Gahn in 1774 at Sweden.Origin of name: from the Latin word "magnes" meaning "magnet", or "magnesia nigri" meaning "black magnesia" (MnO2).
Isolation: it is not normally necessary to make manganese in the laboratory as it is available commercially. Nearly all manganese produced commercially is used in the steel industry as ferromanganese. This made by the reduction of iron oxide, Fe2O3, and managanese dioxide, MnO2, in appropriate proportions with carbon (as coke) in a blast furnace. Pure manganese is available through the electrolysis of manganese sulphate, MnSO4,
Density of solid: 7470 kg m-3
Molar volume: 7.35 cm3
Thermal conductivity: 7.8 W m‑1 K‑1
Melting point: 1519 [1246 °C (2275 °F)] K
Boiling point: 2334 [2061 °C (3742 °F)] K
Enthalpy of fusion: 20.5 kJ mol-1
Atomic radius (empirical): 140 pm
Molecular single bond covalent radius: 119 (coordination number 5) ppm
van der Waals radius: 245 ppm
Pauling electronegativity: 1.55 (Pauling units)
Allred Rochow electronegativity: 1.60 (Pauling units)
Mulliken-Jaffe electronegativity: (no data)
First ionisation energy: 717.28 kJ mol‑1
Second ionisation energy: 1509.03 kJ mol‑1
Third ionisation energy: 3248.5 kJ mol‑1
Universe: 8000 ppb by weight
Crustal rocks: 1100000 ppb by weight
Human: 200 ppb by weight
