  Alanates and boranates are studied intensively because of their potential use
as hydrogen storage materials. In this paper we present a first-principles
study of the electronic structure and the energetics of beryllium boranate,
Be(BH4)2. From total energy calculations we show that - in contrast to the
other boranates and alanates - hydrogen desorption directly to the elements is
likely, and is at least competitive with desorption to the elemental hydride
(BeH2). The formation enthalpy of Be(BH4)2 is only -0.12 eV/H2 (at T=0K). This
low value can be rationalized by the participation of all atoms in the covalent
bonding, in contrast to the ionic bonding observed in other boranates. From
calculations of thermodynamic properties at finite temperature we estimate a
decomposition temperature of 162 K at a pressure of 1 bar.
