Materials Data on K3SiF7 by Materials Project

Abstract

K3SiF7 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of K–F bond distances ranging from 2.69–2.94 Å. In the second K1+ site, K1+ is bonded to six F1- atoms to form KF6 octahedra that share corners with four equivalent SiF6 octahedra and corners with six equivalent KF6 octahedra. The corner-sharing octahedra tilt angles range from 0–69°. There are two shorter (2.81 Å) and four longer (2.96 Å) K–F bond lengths. Si4+ is bonded to six F1- atoms to form SiF6 octahedra that share corners with four equivalent KF6 octahedra. The corner-sharing octahedral tilt angles are 69°. All Si–F bond lengths are 1.72 Å. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to three equivalent K1+ and one Si4+ atom. In the second F1- site, F1- is bonded to six K1+ atoms to form corner-sharing FK6 octahedra. The corner-sharing octahedra tilt angles range from 0–25°. In the third F1- site, F1- is bonded in a single-bond geometry to four K1+ and one Si4+ atom.