Materials Data on CaAlH5 by Materials Project

Abstract

CaAlH5 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ca2+ is bonded to twelve H1- atoms to form distorted CaH12 cuboctahedra that share corners with four equivalent CaH12 cuboctahedra, corners with two equivalent AlH6 octahedra, edges with four equivalent CaH12 cuboctahedra, an edgeedge with one AlH6 octahedra, faces with two equivalent CaH12 cuboctahedra, and faces with three equivalent AlH6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There are a spread of Ca–H bond distances ranging from 2.34–2.66 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with two equivalent CaH12 cuboctahedra, corners with two equivalent AlH6 octahedra, an edgeedge with one CaH12 cuboctahedra, and faces with three equivalent CaH12 cuboctahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Al–H bond distances ranging from 1.69–1.79 Å. There are five inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted single-bond geometry to two equivalent Ca2+ and one Al3+ atom. In the second H1- site, H1- is bonded in a 1-coordinate geometry to three equivalent Ca2+ and one Al3+ atom. In the third H1- site, H1- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one Al3+ atom. In the fourth H1- site, H1- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one Al3+ atom. In the fifth H1- site, H1- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Al3+ atoms.