Magnesium chloride is the name for the chemical compound with the formula MgCl2.
In addition to the anhydrous form, MgCl2 comes in its various hydrates MgCl2·nH2O. These salts are typical ionic halides, being highly soluble in water.
The magnesium chloride can be extracted from brine or sea water. In North America, magnesium chloride is produced primarily from Great Salt Lake brine. It is extracted in a similar process from the Dead Sea in the Jordan Valley.
Magnesium chloride, as the mineral bischofite, is also extracted (by solution mining) out of ancient seabeds, for example, the Zechstein seabed in northwest Europe. Some magnesium chloride is made from evaporation of seawater.
Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form most readily available.