Materials Data on NaZnAsO4 by Materials Project

Abstract

NaZnAsO4 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent ZnO4 tetrahedra, corners with six equivalent AsO4 tetrahedra, and a faceface with one NaO6 pentagonal pyramid. There are three shorter (2.48 Å) and three longer (2.58 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three equivalent O2- atoms. All Na–O bond lengths are 2.40 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 pentagonal pyramids that share corners with six equivalent AsO4 tetrahedra, edges with three equivalent ZnO4 tetrahedra, and a faceface with one NaO6 octahedra. There are three shorter (2.36 Å) and three longer (2.56 Å) Na–O bond lengths. Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with four equivalent AsO4 tetrahedra, and an edgeedge with one NaO6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 64–72°. There are a spread of Zn–O bond distances ranging from 1.97–2.00 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent NaO6 pentagonal pyramids, and corners with four equivalent ZnO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–67°. There is one shorter (1.72 Å) and three longer (1.73 Å) As–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Zn2+, and one As5+ atom. In the second O2- site, O2- is bonded to two Na1+, one Zn2+, and one As5+ atom to form distorted edge-sharing ONa2ZnAs trigonal pyramids. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Zn2+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+, one Zn2+, and one As5+ atom.