Materials Data on Ca3SiO5 by Materials Project

Ca3SiO5 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with four equivalent CaO6 octahedra, corners with four equivalent SiO4 tetrahedra, edges with four equivalent CaO6 octahedra, and faces with two equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 2–74°. There are a spread of Ca–O bond distances ranging from 2.32–2.50 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with twelve equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 52–68°. There is three shorter (1.65 Å) and one longer (1.67 Å) Si–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Ca2+ and one Si4+ atom. In the second O2- site, O2- is bonded to six equivalent Ca2+ atoms to form OCa6 octahedra that share corners with six equivalent OCa3Si tetrahedra and faces with two equivalent OCa6 octahedra. In the third O2- site, O2- is bonded to three equivalent Ca2+ and one Si4+ atom to form corner-sharing OCa3Si tetrahedra. The corner-sharing octahedra tilt angles range from 13–59°.