Materials Data on Ce2AlSi2O9 by Materials Project
Ce2AlSi2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ce+3.50+ sites. In the first Ce+3.50+ site, Ce+3.50+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.20–2.79 Å. In the second Ce+3.50+ site, Ce+3.50+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.32–2.72 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.01 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 38–54°. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Ce+3.50+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ce+3.50+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Al3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ce+3.50+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two Ce+3.50+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Ce+3.50+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Ce+3.50+ and two equivalent Al3+ atoms. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two Ce+3.50+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two Ce+3.50+, one Al3+, and one Si4+ atom.