Magnesium Selenide, MgS

The direct combination of magnesium with selenium is too vigorous to be practically applicable. An impure product is obtained by heating magnesium in nitrogen containing selenium vapour, or by reducing magnesium selenate with carbon in an electric furnace. Fonzes-Diacon prepared it by acting with hydrogen selenide on anhydrous magnesium chloride heated to redness.

MgSe is whitish yellow, crystalline, and decomposed rapidly in moist air, evolving hydrogen selenide. Excess of water appears to form a soluble hydrated selenide.