Mg2NiH: A new hydride phase in the Mg2Ni-H2 system

Abstract

A new hydride phase apart from Mg2NiH4 has been identified in the Mg2Ni-H2 system by pressure-composition-temperature relationships, thermal analyses and X-ray diffraction measurements.The new phase has an approximate composition Mg2NiH and is considered to be the intermediate phase in the Mg2Ni-H2 reaction.The additional hydride phase. Mg2NiH (named as beta-hydride) and the full hydride phase, Mg2NiH4 (named as gamma-hydride) have been shown to crystallize in monoclinic structure. The -beta phase (Mg2NiH) also exhibits a phase transition from monoclinic to cubic structure similar to the gamma-phase (Mg2NiH4).