Zinc Selenide, ZnSe

Zinc Selenide, ZnSe, is produced by heating zinc and selenium together at a high temperature. The amorphous substance thus produced has a brilliant yellow colour, is infusible up to 1100° C., and has a density of 5.29 at 21° C. It is more easily obtained by heating zinc in a current of hydrogen selenide.

Reddish-yellow crystals, of density 5.40 and belonging to the regular system, were obtained by subliming the amorphous form in a current of hydrogen. Yellow crystals of density 5.42 at 15° C. were obtained by heating precipitated zinc selenide, dried in a current of hydrogen, in the electric furnace, and a partially crystalline ZnSe was prepared by similarly heating a mixture of zinc selenate and carbon. Crystals belonging to the hexagonal system were obtained by heating zinc chloride vapour with a mixture of nitrogen and hydrogen selenide. Zinc selenide is thus dimorphous analogously to zinc sulphide. Needle-shaped crystals were also obtained by reducing highly heated zinc selenate with hydrogen.

Crystalline zinc selenide dissolves (evolving hydrogen selenide) in aqueous hydrochloric acid, though gaseous hydrogen chloride, even at a high temperature, has no action on it. It burns in oxygen, forming a basic selenite and selenium dioxide. Chlorine displaces selenium from it.

[Zn] + [Se] = [ZnSe] (cryst.)+40.4 Cal.

The corresponding figures for precipitated ZnSe are 34.0 (crystalline) and 33.60 (amorphous).