Materials Data on NaTi3F7 by Materials Project
NaTi3F7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded to eight F1- atoms to form distorted NaF8 hexagonal bipyramids that share edges with two equivalent NaF8 hexagonal bipyramids and edges with six TiF6 octahedra. There are a spread of Na–F bond distances ranging from 2.28–2.70 Å. There are three inequivalent Ti2+ sites. In the first Ti2+ site, Ti2+ is bonded to six F1- atoms to form TiF6 octahedra that share corners with four equivalent TiF6 octahedra and edges with four equivalent NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 52–69°. There are a spread of Ti–F bond distances ranging from 2.08–2.16 Å. In the second Ti2+ site, Ti2+ is bonded to six F1- atoms to form distorted TiF6 octahedra that share corners with six TiF6 octahedra and edges with two equivalent NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 52–69°. There are a spread of Ti–F bond distances ranging from 2.01–2.25 Å. In the third Ti2+ site, Ti2+ is bonded in a distorted square co-planar geometry to six F1- atoms. There are a spread of Ti–F bond distances ranging from 2.02–2.65 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to four Ti2+ atoms. In the second F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two Ti2+ atoms. In the third F1- site, F1- is bonded in a 4-coordinate geometry to one Na1+ and three Ti2+ atoms. In the fourth F1- site, F1- is bonded in a trigonal planar geometry to one Na1+ and two Ti2+ atoms.