Aluminium selenide

Aluminium selenide is the inorganic compound with the formula Al2Se3.

Preparation
It is a solid prepared by igniting a mixture of the elements at 1000 C:
 * 2 Al +  3 Se  →   Al2Se3

The pure compound is white, but typical samples are coloured. Samples are usually protected from moisture, because they hydrolyze readily, giving off highly toxic hydrogen selenide gas:
 * Al2Se3 +  3 H2O   →   Al2O3  +  3 H2Se

Use
Al2Se3 has been used as a precursor to hydrogen selenide, which is released when the solid is treated with acids.