Materials Data on Sr2LaF7 by Materials Project

Abstract

Sr2LaF7 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to eleven F1- atoms. There are a spread of Sr–F bond distances ranging from 2.49–3.22 Å. In the second Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven F1- atoms. There are a spread of Sr–F bond distances ranging from 2.51–2.57 Å. In the third Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight F1- atoms. There are a spread of Sr–F bond distances ranging from 2.50–2.60 Å. In the fourth Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight F1- atoms. There are a spread of Sr–F bond distances ranging from 2.45–2.63 Å. There are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 11-coordinate geometry to eleven F1- atoms. There are a spread of La–F bond distances ranging from 2.40–2.76 Å. In the second La3+ site, La3+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of La–F bond distances ranging from 2.32–2.87 Å. There are fourteen inequivalent F1- sites. In the first F1- site, F1- is bonded to four Sr2+ atoms to form a mixture of edge and corner-sharing FSr4 tetrahedra. In the second F1- site, F1- is bonded in a 3-coordinate geometry to three equivalent Sr2+ atoms. In the third F1- site, F1- is bonded to four Sr2+ atoms to form a mixture of edge and corner-sharing FSr4 tetrahedra. In the fourth F1- site, F1- is bonded to four Sr2+ atoms to form a mixture of edge and corner-sharing FSr4 tetrahedra. In the fifth F1- site, F1- is bonded to three equivalent Sr2+ and one La3+ atom to form a mixture of edge and corner-sharing FSr3La tetrahedra. In the sixth F1- site, F1- is bonded to four Sr2+ atoms to form a mixture of edge and corner-sharing FSr4 tetrahedra. In the seventh F1- site, F1- is bonded in a trigonal planar geometry to three equivalent La3+ atoms. In the eighth F1- site, F1- is bonded to four Sr2+ atoms to form FSr4 tetrahedra that share corners with thirteen FSr4 tetrahedra and edges with six FSr3La tetrahedra. In the ninth F1- site, F1- is bonded in a 3-coordinate geometry to three equivalent La3+ atoms. In the tenth F1- site, F1- is bonded in a distorted trigonal planar geometry to one Sr2+, three equivalent La3+, and three equivalent F1- atoms. There are one shorter (2.56 Å) and two longer (2.62 Å) F–F bond lengths. In the eleventh F1- site, F1- is bonded in a 4-coordinate geometry to one Sr2+ and three equivalent La3+ atoms. In the twelfth F1- site, F1- is bonded in a 4-coordinate geometry to three equivalent Sr2+, three equivalent La3+, and seven F1- atoms. There are a spread of F–F bond distances ranging from 2.54–2.58 Å. In the thirteenth F1- site, F1- is bonded to four La3+ and one F1- atom to form distorted corner-sharing FLa4F tetrahedra. In the fourteenth F1- site, F1- is bonded in a 3-coordinate geometry to three equivalent Sr2+, one La3+, and three equivalent F1- atoms.