Materials Data on CaW5O7 by Materials Project

Abstract

CaW5O7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.62 Å. There are three inequivalent W+2.40+ sites. In the first W+2.40+ site, W+2.40+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 29–42°. There are a spread of W–O bond distances ranging from 2.12–2.25 Å. In the second W+2.40+ site, W+2.40+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 29–51°. There are a spread of W–O bond distances ranging from 2.13–2.40 Å. In the third W+2.40+ site, W+2.40+ is bonded in a 2-coordinate geometry to six O2- atoms. There are two shorter (2.73 Å) and four longer (2.83 Å) W–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Ca2+ and five W+2.40+ atoms. In the second O2- site, O2- is bonded to two equivalent Ca2+ and two equivalent W+2.40+ atoms to form distorted OCa2W2 tetrahedra that share corners with eight equivalent OCa2W3 square pyramids, corners with four OW6 tetrahedra, and edges with two equivalent OCa2W3 square pyramids. In the third O2- site, O2- is bonded to six W+2.40+ atoms to form distorted OW6 tetrahedra that share a cornercorner with one OCa2W3 square pyramid, corners with three OW6 tetrahedra, edges with two equivalent OCa2W3 square pyramids, and edges with five equivalent OW6 tetrahedra. In the fourth O2- site, O2- is bonded to two equivalent Ca2+ and three W+2.40+ atoms to form distorted OCa2W3 square pyramids that share corners with two equivalent OCa2W3 square pyramids, corners with five OW6 tetrahedra, edges with three equivalent OCa2W3 square pyramids, and edges with three OW6 tetrahedra.