Also known as chloromagnestite, magnesium chloride is a colorless crystalline solid. It is very hygroscopic in nature. It is soluble in water and alcohol. It can be prepared either by heating hydrated magnesium chloride in the presence of hydrogel chloride or by directly heating magnesium ammonium chloride. Anhydrous magnesium chloride crystallizes from magnesium chloride hexahydrate as leaflets. It is electrically conductive. The crystal structure of MgCl₂ is layer like. The structure is cubic close packing with alternate layers of octahedral holes occupied by Mg2+ ions.

Used in salt baths, to maintain humidity, for the synthesis of poly (vinylpyrrolidone) and cellulose acetate nanofibres. It may have general applications in ceramic and textile industries.