Materials Data on K2WSe4 by Materials Project
K2WSe4 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 in a 9-coordinate geometry to nine Se2- atoms. There are a spread of K–Se bond distances ranging from 3.31–3.76 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.57–3.79 Å. W6+ is bonded in a tetrahedral geometry to four Se2- atoms. There are a spread of W–Se bond distances ranging from 2.33–2.35 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four K1+ and one W6+ atom to form distorted SeK4W trigonal bipyramids that share a cornercorner with one SeK5W octahedra, corners with four equivalent SeK4W trigonal bipyramids, and edges with five equivalent SeK5W octahedra. The corner-sharing octahedral tilt angles are 19°. In the second Se2- site, Se2- is bonded to five K1+ and one W6+ atom to form distorted SeK5W octahedra that share corners with four equivalent SeK5W octahedra, a cornercorner with one SeK4W trigonal bipyramid, edges with two equivalent SeK5W octahedra, and edges with five equivalent SeK4W trigonal bipyramids. The corner-sharing octahedra tilt angles range from 20–69°. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to four K1+ and one W6+ atom.