Magnesium is a silvery white light metal. It is a typical metal in that when it loses its outermost electrons it attains the electronic structure of the inert gases; hence, it is a reactive metal. It is produced commercially by electrolysis of magnesium chloride melts and by metallothermic reduction of magnesium oxide with silicon. The largest single use of magnesium is as an alloying element in aluminum alloys. Other uses include its use as a reducing agent in the production of titanium, zirconium, uranium, beryllium, and hafnium. Magnesium enters in the structure of chlorophyll; hence, it is essential for plants.
Relative abundance in Earth’s crust, %
Density (solid), g/cm 3
Density above 650°C (liquid)
1.834–2.647 × 10 −4 T
Lattice constants at 20°C, nm
Melting point, °C
Boiling point, °C
Latent heat of fusion, MJ/kg
