Materials Data on K3AlF6 by Materials Project
K3AlF6 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve equivalent F1- atoms to form KF12 cuboctahedra that share corners with twelve equivalent KF12 cuboctahedra, faces with six equivalent KF12 cuboctahedra, faces with four equivalent KF6 octahedra, and faces with four equivalent AlF6 octahedra. All K–F bond lengths are 3.10 Å. In the second K1+ site, K1+ is bonded to six equivalent F1- atoms to form KF6 octahedra that share corners with six equivalent AlF6 octahedra and faces with eight equivalent KF12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All K–F bond lengths are 2.52 Å. Al3+ is bonded to six equivalent F1- atoms to form AlF6 octahedra that share corners with six equivalent KF6 octahedra and faces with eight equivalent KF12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–F bond lengths are 1.84 Å. F1- is bonded in a 2-coordinate geometry to five K1+ and one Al3+ atom.