beryllium selenide

Beryllium selenide has the molecular formula of BeSe and the molecular weight of 87.9722 g/mol. Its CAS number is 12232-25-6. The literature concerning BeSe is very sparse and the physical constants such as melting point have not been published. It can be prepared by reacting the elements at about 650°C in an inert atmosphere:
Be+ Se ? BeSe
Beryllium selenide crystallizes in the zincblende unit cell with a lattice parameter of 5.1521? . Space group=F43m-Td² . It is not very stable in air and tends to hydrolyze with moisture to form H2Se gas (which is toxic to humans). Because of this instability, BeSe has not been employed by itself as a semiconductor even though its band gap is classified as wide.
Interest in BeSe originates from the fact that formation of ternary BeZnSe or BeMgZnSe compositions allows the formation of deposited layers that can be matched to silicon substrates.
They can also be used to form a blue-green emitting ZnSe-based laser diode grown on GaSe.

Beryllium selenide is prepared from the elements in a Ha stream at 1100°C. Pure Se and pure pulverized Be are placed in a quartz reaction tube in separate boats made of Al2O or BeO, (or at least of quartz). The hydrogen should pass first over the heated Se and then, when laden with its vapor, over the Be. A wash bottle filled with lead acetate is mounted at the exit end of the reaction tube to absorb the very toxic HgSe present in the discharged gas. The Se is heated with a Bunsen burner; the uniform heat of an electric furnace is required for the Be. The BeSe so obtained often shows a tendency to crystallize in long needles.