Basic physical and chemical properties

vlastnosti-hlinikuAluminium, chemical symbol Al, is a base silvery grey, unstable, malleable metal, with very good electrical conductivity.

In nature, it is found mainly in the form of compounds, the best known ore being bauxite.

The aluminium in compounds always has the valence Al+3. In an acid environment it occurs in the form of aluminium cation; in an alkaline environment as aluminium anion [AlO2].

Aluminium in its pure state is very reactive. However, in the air it quickly becomes covered with a thin layer of aluminium oxide Al2O3 which protects it from further oxidation.

Aluminium has very good solubility in diluted acids. However, a concentrated nitric acid covers it with a passivating film of oxide, as does atmospheric oxygen.

The alkali metal hydroxides also dissolve metal aluminium, creating aluminates (AlO2).