Synthesis of diselenides and selenides from elemental selenium

Abstract Sodium hydride is able to reduce elemental selenium to sodium diselenide (Na 2 Se 2 ), but not to sodium selenide (Na 2 Se). Dialkyl diselenides and even dialkyl selenides, including unsymmetrical dialkyl selenides, can be nevertheless synthesized using the proper Se/NaH ratio (1/1 or 1/2).