Aluminium - Al General Information Discovery Aluminium was first prepared in an impure form by Hans Christian Oersted in Copenhagen in 1825, and isolated as an element in 1827 by Wöhler. Appearance Aluminium is a hard and strong, silvery-white metal. An oxide film prevents it from reacting with air and water. Source Aluminium is not found free in nature, but is the most abundant metal in the Earth's crust (8.1%) in the form of minerals such as bauxite and cryolite. Most commercially produced aluminium is obtained by the Bayer process of refining bauxite. In this process the bauxite is refined to pure aluminium oxide, which is mixed with cryolite and then electrolytically reduced to pure aluminium. Uses Aluminium is used in an enormous variety of products, due to its particular properties. It has low density, is non-toxic, has a high thermal conductivity, has excellent corrosion resistance, and can be easily cast, machined and formed. It is also non-magnetic and non-sparking. It is the second most malleable metal and the sixth most ductile. It is therefore extensively used for kitchen utensils, outside building decoration and in any area where a strong, light, easily constructed material is needed. The electrical conductivity of aluminium is about 60% that of copper per unit area of cross-section, but it is nevertheless used in electrical transmission lines because of its low density. Alloys of aluminium with copper, manganese, magnesium and silicon are of vital importance in the construction of aeroplanes and rockets. Aluminium, when evaporated in a vacuum, forms a highly reflective coating for both light and heat which does not deteriorate as does a silver coating. These aluminium coatings are used for telescope mirrors, in decorative paper, packages and toys, and have many other uses. Biological Role Aluminium has no known biological role. It can be accumulated in the body from daily intake, and at one time was suggested as a potential causative factor in Alzheimer's disease (senile dementia). General Information The ancient Greeks and Romans used alum (potassium aluminium sulfate) in medicine as an astringent, and in dyeing as a mordant. Sir Humphry Davy originally proposed the name alumium for the element, which was undiscovered at the time. He later changed the spelling to aluminum and it soon changed again to aluminium. Today the aluminum spelling predominates in the US and Canada whereas aluminium is preferred in the UK and much of the rest of the world. Aluminium oxide, alumina, occurs naturally as corundum and emery, and is used in glass-making and refractories. The precious stones ruby and sapphire contain aluminium with very small amounts of specific impurities.

	Physical Information
	Atomic Number		13
	Relative Atomic Mass (12C=12.000)		26.982
	Melting Point/K		933
	Boiling Point/K		2740
	Density/kg m-3		2698 (293K)
	Ground State Electron Configuration		[Ne]3s23p1
	Electron Affinity(M-M-)/kJ mol-1		-44

	Key Isotopes
	nuclide	26Al	27Al
	atomic mass	25.986	26.982
	natural abundance	0%	100%
	half-life	7.4x105yrs	stable

Other Information
Enthalpy of Fusion/kJ mol-1		10.67
Enthalpy of Vaporisation/kJ mol-1		290.8
Oxidation States
main	Al+3
others	Al0, Al+1
Covalent Bonds /kJ mol-1
Al - H	285
Al - C	225
Al - O	585
Al - F	665
Al - Cl	498
Al - Al	200

	Ionisation Energies/kJ mol-1
	M - M+	577.4
	M+ - M2+	1816.6
	M2+ - M3+	2744.6
	M3+ - M4+	11575
	M4+ - M5+	14839
	M5+ - M6+	18376
	M6+ - M7+	23293
	M7+ - M8+	27457
	M8+ - M9+	31857
	M9+ - M10+	38459