Materials Data on Li2SiF6 by Materials Project

Li2SiF6 is zeta iron carbide-derived structured and crystallizes in the trigonal P321 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six F1- atoms to form distorted LiF6 octahedra that share corners with two equivalent SiF6 octahedra, corners with six equivalent LiF6 octahedra, and edges with two equivalent SiF6 octahedra. The corner-sharing octahedra tilt angles range from 48–59°. There are a spread of Li–F bond distances ranging from 1.99–2.16 Å. In the second Li1+ site, Li1+ is bonded to six F1- atoms to form LiF6 octahedra that share corners with four equivalent SiF6 octahedra, corners with six equivalent LiF6 octahedra, and an edgeedge with one SiF6 octahedra. The corner-sharing octahedra tilt angles range from 44–59°. There are a spread of Li–F bond distances ranging from 2.02–2.19 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six equivalent F1- atoms to form SiF6 octahedra that share corners with six equivalent LiF6 octahedra and edges with three equivalent LiF6 octahedra. The corner-sharing octahedral tilt angles are 48°. All Si–F bond lengths are 1.71 Å. In the second Si4+ site, Si4+ is bonded to six F1- atoms to form SiF6 octahedra that share corners with six equivalent LiF6 octahedra and edges with three equivalent LiF6 octahedra. The corner-sharing octahedra tilt angles range from 44–48°. There is three shorter (1.71 Å) and three longer (1.72 Å) Si–F bond length. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to two Li1+ and one Si4+ atom. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to two Li1+ and one Si4+ atom. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to two Li1+ and one Si4+ atom.