Mechano-chemical synthesis was used to produce complex alkali metal hydrides. Various complex hydrides have been synthesized, for example Li3AlH6, Na3AlH6, (Li-Na)(3)AlH6, (Li-Na-B)(3)AlH6. Complex alkali metal hydrides fabricated by mechano-chemical processes exhibit very good reactivity in hydriding/dehydriding reactions. They have excellent cyclability and cover a wide range of operational temperatures and pressures. (C) 1999 Elsevier Science S.A. All rights reserved.