Materials Data on NaLiTm2F8 by Materials Project

Abstract

NaLiTm2F8 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 2.21–2.54 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 two shorter (1.90 Å) and four longer (2.25 Å) Li–F bond lengths. Tm3+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Tm–F bond distances ranging from 2.18–2.43 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent Li1+ and two equivalent Tm3+ atoms. In the second F1- site, F1- is bonded to one Na1+, one Li1+, and two equivalent Tm3+ atoms to form a mixture of distorted edge and corner-sharing FNaLiTm2 trigonal pyramids. In the third F1- site, F1- is bonded in a trigonal planar geometry to one Na1+ and two equivalent Tm3+ atoms. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Tm3+ atoms. In the fifth F1- site, F1- is bonded to one Na1+, one Li1+, and two equivalent Tm3+ atoms to form a mixture of distorted edge and corner-sharing FNaLiTm2 trigonal pyramids.