Aluminum: Inorganic ChemistryUpdate based on the original article by Allen W. Apblett,Encyclopedia of Inorganic ChemistrySecond Edition, © 2005, John Wiley & Sons, Ltd.

AbstractAluminum is the most abundant metal to be found in the earth's crust (8.1 %). It is component of gemstones and many common minerals such as granite and clays. Aluminum is a very reactive metal and is not found in an uncombined form in nature. However, the use of its compounds has a very long history. For example, the ancient Greeks and Romans used alum as an astringent and as a mordant in dyeing. The pure metal was isolated first by Wohler in 1827. The modern method for obtaining aluminum metal is the electrolysis of alumina dissolved in cryolite. Aluminum can also be produced from clay, but the process is not economically feasible at present. Pure aluminum, a silvery‐white metal, possesses many desirable characteristics. It is light, nonmagnetic, and nonsparking, and is second among all metals in the scale of malleability, and sixth in ductility. It is extensively used for kitchen utensils, outside building materials, airplanes, and in thousands of industrial applications where a strong, light, easily constructed material is needed. Pure aluminum is soft and lacks strength, but when it is alloyed with small amounts of copper, silicon, magnesium, manganese, or other elements these shortcomings can be circumvented. The aluminum compounds of greatest importance are aluminum oxide, aluminum sulfate, aluminum potassium sulfate (alum), and aluminum halides. The oxide, alumina, occurs naturally as ruby (Al2O3), sapphire, corundum, and emery, and is used in glassmaking and refractory ceramic materials. Synthetic ruby and sapphire are used in lasers for producing coherent light. Aluminum nitride, phosphide, and antimonide are important materials for the semiconductor industry. Aluminum halides and oxides are also very important catalyst supports.