White flake,easy to be soluble in water, in moisture air, easy to be deliquescent. At high temperature is can be broken up into hydrogen chloride and magnesium oxide.Used to make refractory material in metallurgy and make all kinds magnesium slat such as magnesium oxide, magnesium hydroxide, magnesium carbonate, cracker kindling and raw material of antifreeze.also used in construction and food and medicine and agriculture field etc.