Facts About Magnesium

Magnesium (Mg)
Credit: Pumbaa/Creative Commons, Andrei Marincas | Shutterstock
Atomic Number: 12
Atomic Symbol: Mg
Atomic Weight: 24.3050
Melting Point: 1,994 F (1,090 C)
Boiling Point: 1,202 F (650 C)

Word origin: From Magnesia, a district in Thessaly, Greece.

Discovery: Joseph Black was the first to recognize magnesium as an element in 1755. Sir Humphry Davy isolated it in 1808, and Antoine A.B. Bussy prepared it in coherent form in 1831.

Properties of magnesium

Magnesium is a light, silvery-white, and fairly tough metal, although it tarnishes slightly when exposed to air.

Finely divided magnesium readily ignites upon heating in air and burns with a bright white flame.

Magnesite (magnesium carbonate)
Magnesite (magnesium carbonate)
Credit: Oreena | Shutterstock

Sources of magnesium

Magnesium is the eighth most abundant element in Earth's outer layer. [See Periodic Table of the Elements]

It is found in large deposits in the form of magnesite, dolomite and other minerals, but does not exist outside of compounds.

In the United States, the metal is primarily obtained through electrolysis of fused magnesium chloride derived from brines, wells and sea water.

Organic magnesium is essential to both plant and animal life. Chlorophylls are magnesium-centered perphyrins.

Uses of magnesium

Uses include flashlight photography, flares and pyrotechnics, including incendiary bombs. It is one-third lighter than aluminum, and in alloys is a critical component for airplane and missile construction. Magnesium boosts the mechanical, fabrication and welding characteristics of aluminum when used as an alloying agent.

Magnesium is used in the production of nodular graphite in cast iron, and as an additive to conventional propellants.

The metal is also used as a reducing agent in the processing of pure uranium and other metals from their salts. Dead-burned magnesite is used for refractory purposes such as brick and liners in furnaces and converters.

Magnesium alloys are often used for tire rims due to their combination of lightness and strength.

The metal also has medical applications. The hydroxide (milk of magnesia), chloride, sulfate (Epsom salts) and citrate are used in medicine. The adult daily nutritional requirement, depending on various factors including weight and size, is about 300 mg per day.

(Source: Los Alamos National Laboratory)

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