What is "sodium hydride"

n. a flammable gray crystalline binary compound (NaH)

Sodium hydride is the chemical compound with the empirical formula Na H. It is primarily used as a strong, yet combustible base in organic synthesis. NaH is representative of the saline hydrides, meaning it is a salt-like hydride, composed of Na and H ions, in contrast to the more molecular hydrides such as borane, methane, ammonia and water. It is an ionic material that is insoluble in organic solvents (although soluble in molten Na), consistent with the fact that H remains an unknown anion in solution. Because of the insolubility of NaH, all reactions involving NaH occur at the surface of the solid.