Magnesium selenide is a stable, light gray to brown crystalline powder. Magnesium selenide can be prepared by reaction of magnesium oxide and selenium. Magnesium selenide is not stable in air and reacts with moisture to form Magnesium hydroxide and Hydrogen selenide. Magnesium selenide is a wide-band semiconductor but is not very stable by itself. MgSe is available commercially as a sputtering or plasma targets for preparing thin-layer electronic structures for diodes, solid-state lasers and the like.