Materials Data on Ca2SiO4 by Materials Project

Abstract

Ca2SiO4 is Ilmenite-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with eight CaO6 octahedra, corners with four equivalent SiO4 tetrahedra, edges with two equivalent CaO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–70°. There are a spread of Ca–O bond distances ranging from 2.31–2.47 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with four equivalent CaO6 octahedra, corners with two equivalent SiO4 tetrahedra, edges with four CaO6 octahedra, and edges with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 62–70°. There are a spread of Ca–O bond distances ranging from 2.33–2.41 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six CaO6 octahedra and edges with three CaO6 octahedra. The corner-sharing octahedra tilt angles range from 50–61°. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like 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 in a 4-coordinate geometry to three Ca2+ and one Si4+ atom.