Materials Data on K2LiAlH6 by Materials Project

Abstract

K2LiAlH6 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve H1- atoms to form KH12 cuboctahedra that share corners with nine KH12 cuboctahedra, corners with three equivalent LiH6 octahedra, faces with seven KH12 cuboctahedra, faces with three equivalent LiH6 octahedra, and faces with four AlH6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are a spread of K–H bond distances ranging from 2.82–2.86 Å. In the second K1+ site, K1+ is bonded to twelve H1- atoms to form KH12 cuboctahedra that share corners with nine KH12 cuboctahedra, corners with three equivalent AlH6 octahedra, faces with seven KH12 cuboctahedra, faces with three equivalent AlH6 octahedra, and faces with four equivalent LiH6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of K–H bond distances ranging from 2.83–2.90 Å. Li1+ is bonded to six H1- atoms to form LiH6 octahedra that share corners with three equivalent KH12 cuboctahedra, corners with three equivalent AlH6 octahedra, faces with seven KH12 cuboctahedra, and a faceface with one AlH6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (2.01 Å) and three longer (2.04 Å) Li–H bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent LiH6 octahedra and faces with eight KH12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. All Al–H bond lengths are 1.79 Å. In the second Al3+ site, Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent KH12 cuboctahedra, faces with six equivalent KH12 cuboctahedra, and faces with two equivalent LiH6 octahedra. All Al–H bond lengths are 1.77 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted linear geometry to four K1+, one Li1+, and one Al3+ atom. In the second H1- site, H1- is bonded in a distorted L-shaped geometry to four K1+, one Li1+, and one Al3+ atom.