Materials Data on SrSc4Si5O17 by Materials Project

Abstract

SrSc4(Si2O7)(Si3O10) crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–2.98 Å. There are two inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to six O2- atoms to form distorted ScO6 pentagonal pyramids that share corners with six SiO4 tetrahedra, an edgeedge with one ScO6 octahedra, and edges with two equivalent ScO6 pentagonal pyramids. There are a spread of Sc–O bond distances ranging from 2.10–2.25 Å. In the second Sc3+ site, Sc3+ is bonded to six O2- atoms to form distorted ScO6 octahedra that share corners with six SiO4 tetrahedra, an edgeedge with one ScO6 octahedra, and an edgeedge with one ScO6 pentagonal pyramid. There are a spread of Sc–O bond distances ranging from 2.07–2.26 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent ScO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Si–O bond distances ranging from 1.63–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent ScO6 octahedra, corners with three equivalent ScO6 pentagonal pyramids, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent ScO6 octahedra, corners with three equivalent ScO6 pentagonal pyramids, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–59°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Sc3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Sc3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Sc3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Sc3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Sc3+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, two equivalent Sc3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, two equivalent Sc3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one Sc3+, and one Si4+ atom.