Materials Data on NaTaWO7 by Materials Project

Abstract

NaTaWO7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share edges with two equivalent NaO8 hexagonal bipyramids, edges with two equivalent WO6 octahedra, and edges with four equivalent TaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.40–2.70 Å. Ta is bonded to six O atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with four equivalent WO6 octahedra, and edges with four equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 38–41°. There is two shorter (1.97 Å) and four longer (2.00 Å) Ta–O bond length. W is bonded to six O atoms to form WO6 octahedra that share corners with two equivalent WO6 octahedra, corners with four equivalent TaO6 octahedra, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–38°. All W–O bond lengths are 1.94 Å. There are four inequivalent O sites. In the first O site, O is bonded in a water-like geometry to two equivalent Na atoms. In the second O site, O is bonded in a 3-coordinate geometry to one Na, one Ta, and one W atom. In the third O site, O is bonded in a bent 150 degrees geometry to two equivalent W atoms. In the fourth O site, O is bonded in a 4-coordinate geometry to two equivalent Na and two equivalent Ta atoms.