DOI: 10.17188/1350896
title: Materials Data on CaAl2SiO6 by Materials Project

description: CaAl2SiO6 is Esseneite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.39–2.63 Å. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.39–2.59 Å. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.60 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.40–2.60 Å. There are eight inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three AlO6 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 1.74–1.79 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three AlO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–62°. There are a spread of Al–O bond distances ranging from 1.73–1.79 Å. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three AlO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–62°. There are a spread of Al–O bond distances ranging from 1.73–1.79 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three AlO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–63°. There are a spread of Al–O bond distances ranging from 1.73–1.79 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.04 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share corners with two SiO4 tetrahedra, corners with four AlO4 tetrahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.24 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.13 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra, corners with four SiO4 tetrahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–2.11 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three AlO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–60°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three AlO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–60°. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three AlO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–59°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three AlO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–60°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OCaAl3 tetrahedra. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two Al3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded to one Ca2+ and three Al3+ atoms to form distorted edge-sharing OCaAl3 tetrahedra. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two Al3+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded to one Ca2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OCaAl3 tetrahedra. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two Al3+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Al3+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the sixteenth O2- site, O2- is bonded to one Ca2+ and three Al3+ atoms to form distorted edge-sharing OCaAl3 tetrahedra. In the seventeenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+ and two Al3+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the nineteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Al3+, and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the twenty-first O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Al3+, and one Si4+ atom. In the twenty-third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Al3+, and one Si4+ atom.