Magnesium chloride is an inorganic chemical compound, formula MgCl2. It has various hydrated forms (MgCl2.XH2O) and anhydrous form (MgCl2) . 

Hydrated magnesium chloride (MgCl2.XH2O) is easily accessible from the natural brine or salt lake brine. Following steps:

1. The brine is evaporated and concentrated to obtain the brine containing magnesium chloride.
2. Cooling crystallization, filtration, washing and other steps, magnesium chloride crystals are obtained.
3. Finally, magnesium chloride crystals were dried and burned to obtain magnesium chloride products. There are other methods to manufacture magnesium chloride.

Anhydrous magnesium chloride (MgCl2) has no crystal water, it contains approximately 25.5% magnesium by mass. Anhydrous magnesium chloride is the primary material for the production of magnesium metal.

Typical applications of magnesium chloride:

1. Magnesium chloride is highly hygroscopic, can be used as a desiccant; 
2. Dissolving in water, magnesium chloride releases large amount of heat, can used as a ice melter.
3. When heating ,magnesium chloride releases chlorine to stop fire, can be used as a flame retardant. Magnesium chloride has many other applications.