Materials Data on Ca11Si4SO18 by Materials Project

Abstract

Ca11Si4SO18 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra and corners with four equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ca–O bond distances ranging from 2.19–2.39 Å. In the second Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to one S2- and five O2- atoms. The Ca–S bond length is 3.25 Å. There are a spread of Ca–O bond distances ranging from 2.32–2.62 Å. In the third Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to one S2- and five O2- atoms. The Ca–S bond length is 3.07 Å. There are a spread of Ca–O bond distances ranging from 2.31–2.76 Å. In the fourth Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ca–O bond lengths are 2.53 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent CaO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. S2- is bonded in a body-centered cubic geometry to eight Ca2+ atoms. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Ca2+ and one Si4+ atom. In the third O2- site, O2- is bonded to six Ca2+ atoms to form distorted corner-sharing OCa6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to six Ca2+ atoms to form distorted corner-sharing OCa6 octahedra. The corner-sharing octahedral tilt angles are 0°.