It is on third lighter than aluminium, and in alloys is essential for airplane and missile construction. It is also used as a reducing agent in the production of pure uranium and other metals from their salts. Dead-burned magnesite is employed for refractory purposes such as brick and liners in furnaces and converters. Organic magnesium compounds are important. Magnesium is an important element in both plant and animal life.
Chlorophylls are magnesium-centered perphyrins.
Great care should be taken in handling magnesium metal, especially in the finely divided state, as serious fires can occur. Water should not be used on burning magnesium or on magnesium fires.