Aluminium diboride (AlB2) is a chemical compound made from the metal aluminium and the metalloid boron.

Structurally the B atoms form graphite-like sheets with Al atoms between them, and this is very similar to the structure of magnesium diboride.

Single crystals of AlB2 exhibit metallic conductivity along the axis parallel to the basal hexagonal plane.

[3] Aluminium boride is considered a hazardous substance as it reacts with acids and hydrogen gas to produce toxic gases.

For example, it reacts with hydrochloric acid to release borane and aluminium chloride.