A THEORETICAL STUDY OF THE ELECTRONIC STRUCTURE AND BONDING OF THE MONOCLINIC PHASE OF Mg2NiH4

PAULA V. JASEN; ESTELA A. GONZÁLEZ; GRACIELA BRIZUELA; OSCAR A. NAGEL; GUSTAVO A. GONZÁLEZ; ALFREDO JUAN

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2007 vol. 32 p. 4943 - 4948

0360-3199

The electronic properties of the Mg2NiH4 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 theirs 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 that with Mg. The principal bonding interaction is Ni sp – H s. Moreover, a small bonding between Ni deg and H 1s is observed. Up the Fermi level, the Ni-H interaction is slightly anti-bonding. The Mg-Ni bonding interactions are weaker in the hydride phase when compared with the pure Mg2Ni alloy. The present study is potentially useful because the alloys Mg-Ni are good materials for hydrogen storage.