Materials Data on NaAlCdF6 by Materials Project

Abstract

NaCdAlF6 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to six F1- atoms to form distorted NaF6 octahedra that share corners with two equivalent CdF7 hexagonal pyramids, corners with five equivalent AlF6 octahedra, edges with two equivalent CdF7 hexagonal pyramids, and edges with two equivalent NaF6 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Na–F bond distances ranging from 2.32–2.56 Å. Cd2+ is bonded to seven F1- atoms to form distorted CdF7 hexagonal pyramids that share corners with two equivalent NaF6 octahedra, corners with two equivalent AlF6 octahedra, edges with four equivalent CdF7 hexagonal pyramids, an edgeedge with one AlF6 octahedra, and edges with two equivalent NaF6 octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are a spread of Cd–F bond distances ranging from 2.29–2.35 Å. Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share corners with two equivalent CdF7 hexagonal pyramids, corners with two equivalent AlF6 octahedra, corners with five equivalent NaF6 octahedra, and an edgeedge with one CdF7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 4–55°. There are a spread of Al–F bond distances ranging from 1.78–1.85 Å. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to two equivalent Cd2+ and one Al3+ atom. In the second F1- site, F1- is bonded to one Na1+ and three equivalent Cd2+ atoms to form a mixture of edge and corner-sharing FNaCd3 tetrahedra. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to two equivalent Na1+ and one Al3+ atom. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to one Na1+, one Cd2+, and one Al3+ atom. In the fifth F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Cd2+, and one Al3+ atom. In the sixth F1- site, F1- is bonded in a linear geometry to two equivalent Al3+ atoms.