Materials Data on SrCaCrF7 by Materials Project
SrCaCrF7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Sr–F bond distances ranging from 2.43–3.05 Å. Ca2+ is bonded to seven F1- atoms to form CaF7 pentagonal bipyramids that share corners with three equivalent CrF6 octahedra, corners with two equivalent CaF7 pentagonal bipyramids, and an edgeedge with one CrF6 octahedra. The corner-sharing octahedra tilt angles range from 33–50°. There are a spread of Ca–F bond distances ranging from 2.29–2.41 Å. Cr3+ is bonded to six F1- atoms to form CrF6 octahedra that share corners with three equivalent CaF7 pentagonal bipyramids and an edgeedge with one CaF7 pentagonal bipyramid. There are a spread of Cr–F bond distances ranging from 1.91–1.96 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to one Sr2+, one Ca2+, and one Cr3+ atom. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Sr2+ and one Cr3+ atom. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to one Sr2+, one Ca2+, and one Cr3+ atom. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to one Sr2+, one Ca2+, and one Cr3+ atom. In the fifth F1- site, F1- is bonded in a distorted trigonal planar geometry to one Sr2+ and two equivalent Ca2+ atoms.