About Hydrides

Hydride Ion Diagram

The hydride ion is the anion of hydrogen, H-. Hydrides are compounds in which one or more hydrogens have nucleophilic/reducing properties, and many are ionic compounds containing the hydride ion. Almost all the elements form binary compounds with hydrogen; these are the simplest hydrides.

Hydrides are divided into three basic types: saline, metallic, and covalent. Saline hydrides, such as sodium hydride and calcium hydride, are often used as portable sources of hydrogen gas. Metallic hydrides, such as titanium hydride, are alloy-like materials that share some properties with metals including luster and electrical conductivity. Covalent hydrides are mostly compounds of hydrogen and nonmetallic elements; they include water, ammonia, hydrogen sulfide, and methane. A fourth group of hydrides, dimeric or polymeric hydrides, give off large amounts of energy when burned and have been investigated for use in rocket fuels.

Hydrides like sodium and potassium hydride are commonly used as reducing agents in chemical synthesis, dessicants or drying agents in laboratory or industrial settings, catalysts, and as chemical means of hydrogen storage, as in nickel-metal hydride battery and hydrogen fuel cell technologies.