Abstract: A hydrogen storage composition has a hydrogenated state and a dehydrogenated state; in the hydrogenated state the composition comprises a metallic hydride having a metallic component which reversibly forms the hydride and a metallic heat transfer medium in intimate contact with the hydride which transfers heat to the hydride for dehydrogenation; in use hydrogen is liberated from the composition with transfer of heat to the heat transfer medium, the hydrogenated state may be regenerated by exposing the composition in a dehydrogenated state to hydrogen gas. In this way a source of hydrogen gas is provided which source may be regenerated.

Abstract: Novel hydrides are produced by mechanically alloying at least two different hydrides, preferably at least one simple alkali metal hydride and at least one complex alkali metal hydride such as an alkali metal aluminum hydride; the method of production is simple and can be carried out at room temperature; the novel hydrides are useful as a source of hydrogen and have the particular advantage that after liberation of the hydrogen, the hydride is readily regenerated from the dehydrogenated hydride.