Materials Data on K3Zn2F7 by Materials Project
K3Zn2F7 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of K–F bond distances ranging from 2.65–2.93 Å. In the second K1+ site, K1+ is bonded to twelve F1- atoms to form KF12 cuboctahedra that share corners with four equivalent KF12 cuboctahedra, faces with four equivalent KF12 cuboctahedra, and faces with eight equivalent ZnF6 octahedra. There are eight shorter (2.91 Å) and four longer (2.93 Å) K–F bond lengths. Zn2+ is bonded to six F1- atoms to form ZnF6 octahedra that share corners with five equivalent ZnF6 octahedra and faces with four equivalent KF12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Zn–F bond distances ranging from 2.04–2.08 Å. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted linear geometry to four equivalent K1+ and two equivalent Zn2+ atoms. In the second F1- site, F1- is bonded in a distorted linear geometry to four K1+ and two equivalent Zn2+ atoms. In the third F1- site, F1- is bonded to five equivalent K1+ and one Zn2+ atom to form a mixture of distorted edge and corner-sharing FK5Zn octahedra. The corner-sharing octahedral tilt angles are 6°.