Materials Data on K3AlH6 by Materials Project

Abstract

K3AlH6 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven H1- atoms. There are a spread of K–H bond distances ranging from 2.56–2.90 Å. In the second K1+ site, K1+ is bonded in a 5-coordinate geometry to three H1- atoms. There are two shorter (2.53 Å) and one longer (2.63 Å) K–H bond lengths. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to seven H1- atoms. There are a spread of K–H bond distances ranging from 2.52–3.00 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six H1- atoms to form edge-sharing AlH6 octahedra. There is two shorter (1.68 Å) and four longer (1.96 Å) Al–H bond length. In the second Al3+ site, Al3+ is bonded to six H1- atoms to form edge-sharing AlH6 octahedra. There is two shorter (1.66 Å) and four longer (1.97 Å) Al–H bond length. There are six inequivalent H1- sites. In the first H1- site, H1- is bonded in a single-bond geometry to three K1+ and one Al3+ atom. In the second H1- site, H1- is bonded to five K1+ atoms to form a mixture of distorted edge and corner-sharing HK5 square pyramids. In the third H1- site, H1- is bonded in a distorted trigonal non-coplanar geometry to one K1+ and two equivalent Al3+ atoms. In the fourth H1- site, H1- is bonded to five K1+ atoms to form a mixture of distorted edge and corner-sharing HK5 trigonal bipyramids. In the fifth H1- site, H1- is bonded in a distorted single-bond geometry to two equivalent K1+ and one Al3+ atom. In the sixth H1- site, H1- is bonded in a distorted water-like geometry to one K1+ and two equivalent Al3+ atoms.