Materials Data on Ca(AlH4)2 by Materials Project

Abstract

Ca(AlH4)2 crystallizes in the trigonal P-3 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six H1- atoms to form CaH6 octahedra that share corners with six AlH4 tetrahedra. All Ca–H bond lengths are 2.20 Å. In the second Ca2+ site, Ca2+ is bonded to six equivalent H1- atoms to form CaH6 octahedra that share corners with six equivalent AlH4 tetrahedra. All Ca–H bond lengths are 2.19 Å. In the third Ca2+ site, Ca2+ is bonded in a 9-coordinate geometry to nine H1- atoms. There are a spread of Ca–H bond distances ranging from 2.29–2.31 Å. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four H1- atoms to form AlH4 tetrahedra that share a cornercorner with one CaH6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of Al–H bond distances ranging from 1.61–1.63 Å. In the second Al3+ site, Al3+ is bonded to four H1- atoms to form AlH4 tetrahedra that share a cornercorner with one CaH6 octahedra. The corner-sharing octahedral tilt angles are 30°. There is one shorter (1.61 Å) and three longer (1.63 Å) Al–H bond length. In the third Al3+ site, Al3+ is bonded to four H1- atoms to form AlH4 tetrahedra that share a cornercorner with one CaH6 octahedra. The corner-sharing octahedral tilt angles are 36°. There are a spread of Al–H bond distances ranging from 1.61–1.64 Å. There are twelve inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the second H1- site, H1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the third H1- site, H1- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the fourth H1- site, H1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the fifth H1- site, H1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the sixth H1- site, H1- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the seventh H1- site, H1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the eighth H1- site, H1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the ninth H1- site, H1- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the tenth H1- site, H1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the eleventh H1- site, H1- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one Al3+ atom. In the twelfth H1- site, H1- is bonded in a bent 150 degrees geometry to one Ca2+ and one Al3+ atom.