Chemical bonding in ternary magnesium hydrides

摘要

The electronic structure of various alkali and alkaline-earth magnesium-based hydrides was investigated in detail. These types of crystalline compounds show MgH4 or MgH6 units ordered within a light-metal framework. We investigated the nature of the chemical bonding in these units by means of quantum chemical calculations of several related clusters. The properties of the charge density of the clusters, within the framework of the theory of atoms in molecules, was analyzed. A further set of computations of the band structure of the solid hydrides was conducted using a state-of the-art density functional-based method and the mechanism of stabilization of the Mg-H units is discussed. It was found that the properties obtained at the molecular level correlate well with those of the solid crystals, indicating the molecular nature of the extended systems in which the units MgHx, x = 4, 6, are stabilized by means of Mg-H closed-shell interactions. (C) 2003 Wiley Periodicals, Inc. [References: 32]