Ionic or saline hydride, is a hydrogen atom bound to an extremely electropositive metal, generally an alkali metal or alkaline earth metal. In these materials the hydrogen atom is viewed as a pseudohalide. Saline hydrides are insoluble in conventional solvents, reflecting their nonmolecular structures. Most ionic hydrides exist as "binary" materials involving only two elements including hydrogen. Ionic hydrides are used as heterogeneous bases and reducing reagents in organic synthesis.[6]