Materials Data on CaScAlSiO6 by Materials Project

Abstract

CaScAlSiO6 is Esseneite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.75 Å. Sc3+ is bonded to six O2- atoms to form ScO6 octahedra that share corners with three equivalent AlO4 tetrahedra, corners with three equivalent SiO4 tetrahedra, and edges with two equivalent ScO6 octahedra. There are a spread of Sc–O bond distances ranging from 1.98–2.32 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent ScO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–63°. There are a spread of Al–O bond distances ranging from 1.74–1.81 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent ScO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–60°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+, one Al3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Sc3+, and one Al3+ atom. In the fourth O2- site, O2- is bonded to one Ca2+, two equivalent Sc3+, and one Al3+ atom to form distorted edge-sharing OCaSc2Al tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Sc3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Sc3+, and one Si4+ atom.