Aluminium oxide
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.
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 It can also be called alumina - although this name is obsolete it is still frequently used in the mining industry.
General
Name
Aluminium oxide
Aluminum oxide (US)
Chemical Formula
Al2O3
Appearance
White crystalline powder or solid
Physical
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
Thermochemistry
ΔfH0liquid
−1620.57 kJ/mol
ΔfH0solid
−1675.69 kJ/mol
S0liquid, 1 bar
67.24 J/mol·K
S0solid
50.9 J/mol·K
Safety
Injestion
Low hazard
Inhalation
May cause irritation or lung damage
Skin
Low hazard
Eyes
Low hazard
SI units were used where possible.