Materials Data on NaLiY2F8 by Materials Project
LiNaY2F8 crystallizes in the orthorhombic Cmcm 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 2.24–2.56 Å. Li1+ is bonded to six F1- atoms to form corner-sharing LiF6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are two shorter (1.93 Å) and four longer (2.26 Å) Li–F bond lengths. Y3+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Y–F bond distances ranging from 2.22–2.47 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Y3+ atoms. In the second F1- site, F1- is bonded to one Na1+, one Li1+, and two equivalent Y3+ atoms to form a mixture of distorted corner and edge-sharing FNaLiY2 trigonal pyramids. In the third F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent Li1+ and two equivalent Y3+ atoms. In the fourth F1- site, F1- is bonded in a trigonal planar geometry to one Na1+ and two equivalent Y3+ atoms.