Materials Data on NaHf2TiF11 by Materials Project
NaHf2TiF11 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Na1+ is bonded to eight F1- atoms to form distorted NaF8 hexagonal bipyramids that share corners with two HfF7 pentagonal bipyramids, edges with two equivalent TiF6 octahedra, and edges with four HfF7 pentagonal bipyramids. There are a spread of Na–F bond distances ranging from 2.24–2.78 Å. There are two inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to seven F1- atoms to form HfF7 pentagonal bipyramids that share a cornercorner with one NaF8 hexagonal bipyramid, corners with three equivalent TiF6 octahedra, a cornercorner with one HfF7 pentagonal bipyramid, edges with two equivalent NaF8 hexagonal bipyramids, and an edgeedge with one HfF7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 0–32°. There are a spread of Hf–F bond distances ranging from 1.96–2.16 Å. In the second Hf4+ site, Hf4+ is bonded to seven F1- atoms to form HfF7 pentagonal bipyramids that share a cornercorner with one NaF8 hexagonal bipyramid, corners with three equivalent TiF6 octahedra, a cornercorner with one HfF7 pentagonal bipyramid, edges with two equivalent NaF8 hexagonal bipyramids, and an edgeedge with one HfF7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 5–32°. There are a spread of Hf–F bond distances ranging from 1.96–2.15 Å. Ti2+ is bonded to six F1- atoms to form TiF6 octahedra that share corners with six HfF7 pentagonal bipyramids and edges with two equivalent NaF8 hexagonal bipyramids. There are a spread of Ti–F bond distances ranging from 2.09–2.15 Å. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Na1+, one Hf4+, and one Ti2+ atom. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Na1+, one Hf4+, and one Ti2+ atom. In the third F1- site, F1- is bonded in a bent 150 degrees geometry to one Na1+ and one Hf4+ atom. In the fourth F1- site, F1- is bonded in a linear geometry to one Na1+ and one Hf4+ atom. In the fifth F1- site, F1- is bonded in a linear geometry to one Hf4+ and one Ti2+ atom. In the sixth F1- site, F1- is bonded in a linear geometry to one Hf4+ and one Ti2+ atom. In the seventh F1- site, F1- is bonded in a trigonal planar geometry to one Na1+ and two Hf4+ atoms. In the eighth F1- site, F1- is bonded in a linear geometry to two Hf4+ atoms.