Ca(BH4)(2)-Mg2NiH4: on the pathway to a Ca(BH4)(2) system with a reversible hydrogen cycle

The Ca(BH4)(2)-Mg2NiH4 system presented here is, to the best of our knowledge, the first described Ca(BH4)(2)-based hydride composite that reversibly transfers boron from the Ca-based compound(s) to the reaction partner. The ternary boride MgNi2.5B2 is formed upon dehydrogenation and the formation of Ca(BH4)(2) upon rehydrogenation is confirmed.