Materials Data on KCu4(AsO4)3 by Materials Project

Abstract

KCu4(AsO4)3 is Esseneite-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded to eight O2- atoms to form distorted KO8 hexagonal bipyramids that share corners with two equivalent AsO4 tetrahedra, edges with two equivalent KO8 hexagonal bipyramids, edges with four equivalent CuO6 octahedra, and edges with three AsO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.68–2.80 Å. There are three inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share corners with six AsO4 tetrahedra, edges with two equivalent KO8 hexagonal bipyramids, and an edgeedge with one CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.95–2.57 Å. In the second Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.92 Å) and two longer (1.94 Å) Cu–O bond length. In the third Cu2+ site, Cu2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cu–O bond distances ranging from 1.99–2.59 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one KO8 hexagonal bipyramid, corners with four equivalent CuO6 octahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedra tilt angles range from 39–60°. There are a spread of As–O bond distances ranging from 1.72–1.76 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent CuO6 octahedra and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedra tilt angles range from 56–61°. There is two shorter (1.71 Å) and two longer (1.79 Å) As–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent K1+, one Cu2+, and one As5+ atom to form a mixture of distorted corner and edge-sharing OK2CuAs trigonal pyramids. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Cu2+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cu2+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cu2+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, two Cu2+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, two Cu2+, and one As5+ atom.