Materials Data on Na2AlZnF7 by Materials Project

Abstract

Na2ZnAlF7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to eight F1- atoms to form NaF8 hexagonal bipyramids that share corners with two equivalent NaF8 hexagonal bipyramids, corners with two equivalent AlF6 octahedra, edges with four equivalent NaF8 hexagonal bipyramids, edges with two equivalent AlF6 octahedra, and edges with four equivalent ZnF6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Na–F bond distances ranging from 2.25–2.74 Å. In the second Na1+ site, Na1+ is bonded to eight F1- atoms to form distorted NaF8 hexagonal bipyramids that share edges with six NaF8 hexagonal bipyramids, edges with two equivalent ZnF6 octahedra, and edges with four equivalent AlF6 octahedra. There are four shorter (2.50 Å) and four longer (2.79 Å) Na–F bond lengths. Zn2+ is bonded to six F1- atoms to form ZnF6 octahedra that share corners with two equivalent ZnF6 octahedra, corners with four equivalent AlF6 octahedra, and edges with six NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 38–54°. There are two shorter (2.03 Å) and four longer (2.05 Å) Zn–F bond lengths. Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share corners with two equivalent NaF8 hexagonal bipyramids, corners with four equivalent ZnF6 octahedra, and edges with six NaF8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There is four shorter (1.82 Å) and two longer (1.86 Å) Al–F bond length. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to two Na1+, one Zn2+, and one Al3+ atom. In the second F1- site, F1- is bonded in a 4-coordinate geometry to three Na1+ and one Al3+ atom. In the third F1- site, F1- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two equivalent Zn2+ atoms.