Materials Data on NaCr(WO4)2 by Materials Project
NaCr(WO4)2 is zeta iron carbide-derived structured and crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with eight equivalent WO6 octahedra and edges with two equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 36–57°. There are a spread of Na–O bond distances ranging from 2.38–2.42 Å. W6+ is bonded to six O2- atoms to form distorted WO6 octahedra that share corners with four equivalent NaO6 octahedra, corners with four equivalent CrO6 octahedra, and edges with two equivalent WO6 octahedra. The corner-sharing octahedra tilt angles range from 36–57°. There are a spread of W–O bond distances ranging from 1.77–2.25 Å. Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with eight equivalent WO6 octahedra and edges with two equivalent CrO6 octahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of Cr–O bond distances ranging from 2.01–2.06 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent W6+ and one Cr3+ atom. In the second O2- site, O2- is bonded in a trigonal planar geometry to one Na1+ and two equivalent W6+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one W6+ and two equivalent Cr3+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Na1+ and one W6+ atom.