Aluminium selenide

Aluminium selenide is the inorganic compound with the formula Al₂Se₃.

It is a solid prepared by igniting a mixture of the elements at 1,000 °C (1,830 °F):

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

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