Materials Data on K2CuBr3 by Materials Project

Abstract

K2CuBr3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to seven Br1- atoms to form distorted KBr7 pentagonal bipyramids that share corners with four equivalent KBr7 pentagonal bipyramids, corners with three equivalent CuBr4 tetrahedra, edges with eight KBr7 pentagonal bipyramids, edges with three equivalent CuBr4 tetrahedra, and faces with two equivalent KBr7 pentagonal bipyramids. There are a spread of K–Br bond distances ranging from 3.35–3.46 Å. In the second K1+ site, K1+ is bonded to seven Br1- atoms to form distorted KBr7 pentagonal bipyramids that share corners with six KBr7 pentagonal bipyramids, a cornercorner with one CuBr4 tetrahedra, edges with ten KBr7 pentagonal bipyramids, and edges with four equivalent CuBr4 tetrahedra. There are a spread of K–Br bond distances ranging from 3.30–3.48 Å. Cu1+ is bonded to four Br1- atoms to form CuBr4 tetrahedra that share corners with four KBr7 pentagonal bipyramids, corners with two equivalent CuBr4 tetrahedra, and edges with seven KBr7 pentagonal bipyramids. There are a spread of Cu–Br bond distances ranging from 2.46–2.55 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 6-coordinate geometry to four K1+ and two equivalent Cu1+ atoms. In the second Br1- site, Br1- is bonded to five K1+ and one Cu1+ atom to form distorted edge-sharing BrK5Cu octahedra. In the third Br1- site, Br1- is bonded in a 6-coordinate geometry to five K1+ and one Cu1+ atom.