Structure of strontium hydroxide octahydrate, Sr(OH)2.8H2O, at 20, 100 and 200 K from neutron diffraction

The crystal structure of Sr(OH)2*8H2O has been determined at 20, 100 and 200 K from neutron diffraction data. The structure consists of double layers of H2O and OH- ions separated by Sr2+ along the c axis. The Sr2+ ions are eight-coordinated by water O atoms in a square antiprism configuration. Each H2O molecule is engaged in three hydrogen bonds. The OH- ions form chains of acceptor and donor bonds along the fourfold axis with O atoms engaged in four bonds with H2O molecules, such that both non-equivalent O atoms have square-pyramidal environments of five H atoms and the overall bonding configurations of distorted octahedra.