Materials Data on K3TlF6 by Materials Project

K3TlF6 crystallizes in the cubic Fd-3 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a q6 geometry to twelve equivalent F1- atoms. All K–F bond lengths are 3.25 Å. In the second K1+ site, K1+ is bonded to twelve equivalent F1- atoms to form KF12 cuboctahedra that share faces with four equivalent KF6 octahedra and faces with four equivalent TlF6 octahedra. All K–F bond lengths are 3.23 Å. In the third K1+ site, K1+ is bonded to six F1- atoms to form KF6 octahedra that share corners with six TlF6 octahedra and a faceface with one KF12 cuboctahedra. The corner-sharing octahedra tilt angles range from 19–40°. There are three shorter (2.59 Å) and three longer (2.60 Å) K–F bond lengths. In the fourth K1+ site, K1+ is bonded in a distorted square co-planar geometry to four F1- atoms. There are two shorter (2.65 Å) and two longer (2.72 Å) K–F bond lengths. There are two inequivalent Tl3+ sites. In the first Tl3+ site, Tl3+ is bonded to six equivalent F1- atoms to form TlF6 octahedra that share corners with six equivalent KF6 octahedra. The corner-sharing octahedral tilt angles are 40°. All Tl–F bond lengths are 2.20 Å. In the second Tl3+ site, Tl3+ is bonded to six equivalent F1- atoms to form TlF6 octahedra that share corners with six equivalent KF6 octahedra and faces with two equivalent KF12 cuboctahedra. The corner-sharing octahedral tilt angles are 19°. All Tl–F bond lengths are 2.19 Å. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to three K1+ and one Tl3+ atom. In the second F1- site, F1- is bonded in a 3-coordinate geometry to three K1+ and one Tl3+ atom.