A theoretical study of the electronic structure and bonding of the monoclinic phase of Mg2NiH4Mg2NiH4

The electronic properties of the Mg2NiH4Mg2NiH4 monoclinic phase are calculated using a density functional approach calculation. The crystalline parameters and interatomic distances calculated are close to the experimental values within a 3% error. We also evaluate the density of states (DOS) and character of the chemical bonding for the hydrogen's located in their equilibrium positions. While the Ni–Mg interaction is dominant in the pure alloy, in the hydride the hydrogen atoms present a bonding much more developed with Ni than with Mg. The principal bonding interaction is Ni sp–H s. Moreover, a small bonding between Ni degdeg and H 1s is observed. Up the Fermi level, the Ni–H interaction is slightly antibonding. The Mg–Ni bonding interactions are weaker in the hydride phase when compared with the pure Mg2NiMg2Ni alloy. The present study is potentially useful because the alloys Mg–Ni are good materials for hydrogen storage.