Electronic structure of BaReH9

BaReH9 and hydrides such as A(2)'TH9 (A'=Na, K, T=Tc, Re) present an unusual high hydrogen coordination around the transition metal. This feature makes these hydrides interesting due to the hydrogen to metal ratio, the largest encountered among the known ternary hydrides. With the aim of improving the understanding of the chemical bonding in this class of compounds, we have investigated the electronic structure of the new hydride BaReH9 by calculating ab initio the energy bands, density of states and the partial wave and symmetry analysis of the density of states at each atomic site. We found that this hydride is an insulator with a large energy gap as experiment indicates. The partial wave and symmetry analysis of the density of states show that the electronic properties of this compound are strongly dominated by the Re-H bonding interactions, in the ReH9 cluster. (C) 1999 Elsevier Science S.A. All rights reserved.