Aluminium diboride

Aluminium diboride (AlB₂) is a chemical compound made from the metal aluminium and the metalloid boron. It is one of two compounds of aluminium and boron, the other being AlB₁₂, which are both commonly referred to as aluminium boride.

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.

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.