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Aluminium oxide

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Name Aluminium oxide
Aluminum oxide (US)
Chemical Formula Al2O3
Appearance White crystalline powder or solid
Formula weight 101.96 amu
Melting point at SP 2303 K
Boiling point at SP 3250 K
Density 3.97 × 103 kg/m3
Crystal structure Trigonal (hex)
Solubility Insoluble
ΔfH0liquid −1620.57 kJ/mol
ΔfH0solid −1675.69 kJ/mol
S0liquid, 1 bar 67.24 J/mol·K
S0solid 50.9 J/mol·K
Injestion Low hazard
Inhalation May cause irritation or lung damage
Skin Low hazard
Eyes Low hazard
SI units were used where possible.
Aluminium oxide (also Aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. It can also be called alumina - although this name is obsolete it is still frequently used in the mining industry.

Aluminium oxide is the main component of the principal ore of aluminium (bauxite), and the main component of the gems ruby and sapphire.

Aluminium oxide is responsible for metallic aluminium's resistance to weathering. Metallic aluminium is very reactive with atmospheric oxygen, and a thin layer of aluminium oxide quickly forms on any exposed aluminium surface. This layer protects the metal from further oxidation.

Powdered aluminium oxide is frequently used as a medium for chromatography.

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