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Atomic Number: 12
Atomic Symbol: Mg
Atomic Weight: 24.305
Electron Configuration: [Ne]3s2
History
(Magnesia, district in Thessaly) Compounds of magnesium have long
been known. Black recognized magnesium as an element in 1755. Davy isolated it
in 1808 and Bussy prepared it in coherent form in 1831. Magnesium is the eighth
most abundant element in the earth's crust. It does not occur uncombined, but is
found in large deposits in the form of magnesite, dolomite, and other minerals.
Sources
The metal is now principally obtained in the U.S. by electrolysis of
fused magnesium chloride derived from brines, wells, and sea water.
Properties
Magnesium is a light, silvery-white, and fairly tough metal. It
tarnishes slightly in air, and finely divided magnesium readily ignites upon
heating in air and burns with a dazzling white flame.
Uses
Uses include flashlight photography, flares, and pyrotechnics,
including incendiary bombs. It is one third lighter than aluminum, and in alloys
is essential for airplane and missile construction. The metal improves the
mechanical, fabrication, and welding characteristics of aluminum when used as an
alloying agent. Magnesium is used in producing nodular graphite in cast iron,
and is used as an additive to conventional propellants.
It is also used as a reducing agent in the production of pure
uranium and other metals from their salts. The hydroxide (milk of magnesia),
chloride, sulfate (Epsom salts), and citrate are used in medicine. Dead-burned
magnesite is employed for refractory purposes such as brick and liners in
furnaces and converters.
Compounds
Organic magnesium is important in both plant and animal life.
Chlorophylls are magnesium-centered perphyrins.
The adult daily nutritional requirement, which is affected by
various factors include weight and size, is about 300 mg/day.
Handling
Because serious fires can occur, great care should be taken in
handling magnesium metal, especially in the finely divided state. Water should
not be used on burning magnesium or on magnesium fires.
Sources: CRC Handbook of Chemistry and
Physics and the American Chemical Society.
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