Materials Data on K3AlH6 by Materials Project

Abstract

K3AlH6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six H1- atoms to form KH6 octahedra that share corners with six equivalent AlH6 octahedra. The corner-sharing octahedra tilt angles range from 21–25°. There are a spread of K–H bond distances ranging from 2.57–2.59 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight H1- atoms. There are a spread of K–H bond distances ranging from 2.71–3.03 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with six equivalent KH6 octahedra. The corner-sharing octahedra tilt angles range from 21–25°. There is four shorter (1.78 Å) and two longer (1.79 Å) Al–H bond length. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a 1-coordinate geometry to four K1+ and one Al3+ atom. In the second H1- site, H1- is bonded in a 1-coordinate geometry to four K1+ and one Al3+ atom. In the third H1- site, H1- is bonded in a 4-coordinate geometry to three K1+ and one Al3+ atom.