Materials Data on NaLiYb2F8 by Materials Project

Abstract

NaLiYb2F8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded in a 7-coordinate geometry to seven F1- atoms. There are a spread of Na–F bond distances ranging from 2.16–2.47 Å. Li1+ is bonded to six F1- atoms to form distorted corner-sharing LiF6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Li–F bond distances ranging from 1.97–2.23 Å. Yb3+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Yb–F bond distances ranging from 2.25–2.35 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to one Na1+ and two equivalent Yb3+ atoms. In the second F1- site, F1- is bonded to one Na1+, one Li1+, and two equivalent Yb3+ atoms to form distorted FNaLiYb2 trigonal pyramids that share corners with two equivalent FLi2Yb2 tetrahedra, corners with six FNaLiYb2 trigonal pyramids, an edgeedge with one FLi2Yb2 tetrahedra, and edges with three FNaLiYb2 trigonal pyramids. In the third F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Yb3+ atoms. In the fourth F1- site, F1- is bonded to one Na1+, one Li1+, and two equivalent Yb3+ atoms to form distorted FNaLiYb2 trigonal pyramids that share corners with two equivalent FLi2Yb2 tetrahedra, corners with six FNaLiYb2 trigonal pyramids, an edgeedge with one FLi2Yb2 tetrahedra, and edges with three FNaLiYb2 trigonal pyramids. In the fifth F1- site, F1- is bonded to two equivalent Li1+ and two equivalent Yb3+ atoms to form distorted FLi2Yb2 tetrahedra that share corners with two equivalent FLi2Yb2 tetrahedra, corners with eight FNaLiYb2 trigonal pyramids, and edges with four FNaLiYb2 trigonal pyramids.