Materials Data on SrSi2O5 by Materials Project

Abstract

SrSi2O5 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with eight equivalent SrO12 cuboctahedra, corners with four equivalent SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, edges with three equivalent SiO4 tetrahedra, faces with three equivalent SrO12 cuboctahedra, and faces with four equivalent SiO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.66–3.03 Å. There are two 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 SrO12 cuboctahedra, corners with four equivalent SiO6 octahedra, and edges with three equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 53–60°. There is one shorter (1.62 Å) and three longer (1.68 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with two equivalent SiO6 octahedra, corners with four equivalent SiO4 tetrahedra, an edgeedge with one SrO12 cuboctahedra, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 46°. There are a spread of Si–O bond distances ranging from 1.72–1.95 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three equivalent Sr2+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three equivalent Sr2+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sr2+ and two Si4+ atoms.