Materials Data on Li5CuF8 by Materials Project
Li5CuF8 is Spinel-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four F1- atoms to form LiF4 tetrahedra that share corners with three equivalent CuF6 octahedra and corners with nine equivalent LiF6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is one shorter (1.85 Å) and three longer (1.96 Å) Li–F bond length. In the second Li1+ site, Li1+ is bonded to six F1- atoms to form LiF6 octahedra that share corners with six equivalent LiF4 tetrahedra, edges with two equivalent CuF6 octahedra, and edges with four equivalent LiF6 octahedra. There are two shorter (1.95 Å) and four longer (2.10 Å) Li–F bond lengths. Cu3+ is bonded to six equivalent F1- atoms to form CuF6 octahedra that share corners with six equivalent LiF4 tetrahedra and edges with six equivalent LiF6 octahedra. All Cu–F bond lengths are 1.94 Å. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a rectangular see-saw-like geometry to three Li1+ and one Cu3+ atom. In the second F1- site, F1- is bonded to four Li1+ atoms to form distorted corner-sharing FLi4 tetrahedra.