Materials Data on K2CuF4 by Materials Project

Abstract

K2CuF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mcm 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 2.64–2.95 Å. In the second 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 2.65–2.95 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to six F1- atoms to form corner-sharing CuF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Cu–F bond distances ranging from 1.94–2.23 Å. In the second Cu2+ site, Cu2+ is bonded to six F1- atoms to form corner-sharing CuF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.98 Å) and four longer (2.09 Å) Cu–F bond lengths. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded to five K1+ and one Cu2+ atom to form distorted FK5Cu octahedra that share corners with seventeen FK5Cu octahedra, edges with eight FK5Cu octahedra, and faces with four equivalent FK4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–56°. In the second F1- site, F1- is bonded to four equivalent K1+ and two equivalent Cu2+ atoms to form distorted FK4Cu2 octahedra that share corners with fourteen FK5Cu octahedra, edges with two equivalent FK4Cu2 octahedra, and faces with eight FK5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–56°. In the third F1- site, F1- is bonded to five K1+ and one Cu2+ atom to form distorted FK5Cu octahedra that share corners with seventeen FK4Cu2 octahedra, edges with eight FK5Cu octahedra, and faces with four equivalent FK4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–59°. In the fourth F1- site, F1- is bonded to four equivalent K1+ and two equivalent Cu2+ atoms to form distorted FK4Cu2 octahedra that share corners with fourteen FK5Cu octahedra, edges with two equivalent FK4Cu2 octahedra, and faces with eight FK5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–59°.