Materials Data on K2LiAlF6 by Materials Project

Abstract

K2LiAlF6 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 F1- atoms to form distorted KF12 cuboctahedra that share corners with nine KF12 cuboctahedra, corners with three equivalent AlF6 octahedra, faces with seven KF12 cuboctahedra, faces with three equivalent AlF6 octahedra, and faces with four equivalent LiF6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are a spread of K–F bond distances ranging from 2.78–3.10 Å. In the second K1+ site, K1+ is bonded to twelve F1- atoms to form KF12 cuboctahedra that share corners with nine KF12 cuboctahedra, corners with three equivalent LiF6 octahedra, faces with seven KF12 cuboctahedra, faces with three equivalent LiF6 octahedra, and faces with four AlF6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of K–F bond distances ranging from 2.85–2.95 Å. Li1+ is bonded to six F1- atoms to form distorted LiF6 octahedra that share corners with three equivalent KF12 cuboctahedra, corners with three equivalent AlF6 octahedra, faces with seven KF12 cuboctahedra, and a faceface with one AlF6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (2.00 Å) and three longer (2.19 Å) Li–F bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six equivalent F1- atoms to form AlF6 octahedra that share corners with six equivalent KF12 cuboctahedra, faces with six equivalent KF12 cuboctahedra, and faces with two equivalent LiF6 octahedra. All Al–F bond lengths are 1.83 Å. In the second Al3+ site, Al3+ is bonded to six equivalent F1- atoms to form AlF6 octahedra that share corners with six equivalent LiF6 octahedra and faces with eight KF12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. All Al–F bond lengths are 1.84 Å. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Li1+, and one Al3+ atom. In the second F1- site, F1- is bonded in a 6-coordinate geometry to four K1+, one Li1+, and one Al3+ atom.