Facts About Aluminum

Atomic Number: 13
Atomic Symbol: Al
Atomic Weight: 26.981538

Melting Point: 1,221 F (660.32 C)
Boiling Point: 4,566 F (2,519 C)

Word origin: From the Latin word alumen, alum. In 1807, Sir Humphry Davy proposed the namealuminium for the metal, undiscovered at that time, and later agreed to change it to aluminum. Shortly thereafter, the name aluminium was adopted to conform with the "ium" ending of most elements.

Aluminium was also the accepted spelling in the United States until 1925, when the American Chemical Society decided to use aluminum thereafter in their publications.

Discovery: The ancient Greeks and Romans used alum as an astringent and as a mordant in dyeing. In 1761, de Morveau proposed the name alumine for the base in alum, and Lavoisier, in 1787, thought this to be the oxide of a still undiscovered metal.

Friedrich Wohler is generally credited with having isolated the metal in 1827, although an impure form was prepared by Hans Christian Oersted two years earlier.

Properties of aluminum

Pure aluminum is a silvery-white metal that possesses many useful features. It is light, nonmagnetic and nonsparking. It is the second most malleable metal and sixth most ductile.

ruby, aluminum
Ruby crystals (aluminum oxide) in a quartz matrix.
Credit: Jens Mayer | Shutterstock

Aluminum’s most important compounds are aluminum oxide, sulfate, and a soluble sulfate with potassium (known as alum).

Sources of aluminum

Aluminum is the most abundant metal in the earth’s crust (8.1 percent), but it is never found free in nature. It is found in granite, cryolite and other common minerals. The oxide, alumina, occurs naturally as ruby, sapphire, corundum and emery.

Today, however, most aluminum we get is from an artificial mixture of sodium, aluminum and calcium fluorides. Aluminum can also be produced from clay, but the process is not economically feasible today.

Uses of aluminum

Aluminum is commonly used for kitchen utensils, exterior building siding and in thousands of industrial applications. It is sometimes used in electrical transmission lines because of its light weight, despite the fact that its electrical conductivity is only about 60 percent that of copper.

Pure aluminum is soft and lacks strength so it is typically alloyed with small amounts of copper, magnesium, silicon, manganese, and other elements to make it sturdier and more useful.

These aluminum alloys are critical to the success of modern aircraft and rockets. When evaporated in a vacuum, aluminum forms a highly reflective coating for both visible light and radiant heat. The coating forms a thin layer of protective oxide and does not deteriorate, meaning it can coat telescope mirrors as well as make decorative paper and toys.

Alumina and ruby, sapphire, corundum, and emery are used in glassmaking and refractories. Synthetic ruby and sapphire, made with aluminum, are used in lasers for producing coherent light.

(Source: Los Alamos National Laboratory)

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