Materials Data on Ca2Ti2SiGeO10 by Materials Project

Abstract

Ca2Ti2GeSiO10 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.29–2.57 Å. In the second Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.65 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with two equivalent GeO4 tetrahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–39°. There are a spread of Ti–O bond distances ranging from 1.88–2.05 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 43–56°. All Ge–O bond lengths are 1.77 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 37–52°. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Ti4+, and one Si4+ atom. In the second O2- site, O2- is bonded to two Ca2+, one Ti4+, and one Ge4+ atom to form distorted corner-sharing OCa2TiGe tetrahedra. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ti4+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ti4+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Ti4+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and two equivalent Ti4+ atoms.