Energetics and electronic properties of Mg7TMH16 (TM=Sc, Ti, V, Y, Zr, Nb): An ab initio study

First-principles calculations have been performed on the face-centered cubic (FCC) magnesium–transition metal (TM) hydrides Mg7TMH16 (TM=Sc, Ti, V, Y, Zr, Nb). The cohesive energies are calculated to analyze the stability, and the obtained enthalpies of formation for hydrides Mg7TMH16 have been used to investigate the possible pathways of formation reaction. The calculated enthalpy changes show that the decomposition temperatures of Mg7TMH16 are lower than that of MgH2. The electronic densities of states reveal that all the hydrides studied here exhibit metallic characteristics. The bonding nature of Mg7TMH16 is investigated, showing stronger covalent bonding between TM and H than between Mg and H.