Materials Data on Ce2Ti2SiO9 by Materials Project

Abstract

Ce2Ti2SiO9 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ce3+ sites. In the first Ce3+ site, Ce3+ is bonded in a 1-coordinate geometry to ten O2- atoms. There are a spread of Ce–O bond distances ranging from 2.21–3.02 Å. In the second Ce3+ site, Ce3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ce–O bond distances ranging from 2.32–2.71 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent TiO6 octahedra, a cornercorner with one SiO4 tetrahedra, and an edgeedge with one TiO6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Ti–O bond distances ranging from 1.86–2.31 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with two equivalent SiO4 tetrahedra, and edges with two equivalent TiO6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Ti–O bond distances ranging from 1.92–2.04 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three TiO6 octahedra. The corner-sharing octahedra tilt angles range from 27–57°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Ce3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Ce3+ and one Ti4+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Ce3+, one Ti4+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted L-shaped geometry to one Ce3+ and two equivalent Ti4+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Ce3+, one Ti4+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ce3+ and two equivalent Ti4+ atoms.