Materials Data on Si2WO7 by Materials Project
WSi2O7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded to six O2- atoms to form WO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent WO6 octahedra. There are a spread of W–O bond distances ranging from 1.88–2.05 Å. In the second W6+ site, W6+ is bonded to six O2- atoms to form WO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent WO6 octahedra. There are a spread of W–O bond distances ranging from 1.89–2.06 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two WO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–57°. There are a spread of Si–O bond distances ranging from 1.54–1.84 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two WO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Si–O bond distances ranging from 1.61–1.71 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a single-bond geometry to one Si4+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one W6+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to two W6+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one W6+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two W6+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms.