Structures of aluminium-based light weight hydrides

Light weight hydrides based on aluminium are among the most promising materials for hydrogen storage applications since the hydrogen content is up to 11 wt%. The crystal structures of many promising aluminium-based compounds have been determined and refined during the last years. This review gives an overview of structures of tetra-alanates (with AlH4 tetrahedra), hexa-alanates (with AlH6 octahedra) and different modifications of AlH3. The structure determinations are based on powder diffraction with X-rays, synchrotron X-rays and neutrons. In most structural work neutron diffraction has been used in order to determine accurate hydrogen/deuterium positions. In addition, density functional theory has been used both to predict new structures among these compounds and in combination with experimental work.