DOI: 10.17188/1708050
title: Materials Data on CaAl2(Si3O10)2 by Materials Project

description: CaAl2(Si3O10)2 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. Ca is bonded to eight O atoms to form distorted CaO8 hexagonal bipyramids that share corners with two SiO4 tetrahedra, an edgeedge with one SiO4 tetrahedra, and edges with two AlO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.79 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra and an edgeedge with one CaO8 hexagonal bipyramid. There are a spread of Al–O bond distances ranging from 1.72–1.78 Å. In the second Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra and an edgeedge with one CaO8 hexagonal bipyramid. There is two shorter (1.72 Å) and two longer (1.80 Å) Al–O bond length. There are six inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO8 hexagonal bipyramid, corners with two equivalent AlO4 tetrahedra, and corners with two SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO4 tetrahedra, corners with two SiO4 tetrahedra, and an edgeedge with one CaO8 hexagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO8 hexagonal bipyramid, a cornercorner with one AlO4 tetrahedra, and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.64 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. There are twenty inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the third O site, O is bonded in a 2-coordinate geometry to one Ca, one Al, and one Si atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the sixth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the seventh O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Al, and one Si atom. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca, one Al, and one Si atom. In the tenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the eleventh O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twelfth O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Al, and one Si atom. In the thirteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fourteenth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the fifteenth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the sixteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the seventeenth O site, O is bonded in a single-bond geometry to one Ca atom. In the eighteenth O site, O is bonded in a 1-coordinate geometry to one Ca and one O atom. The O–O bond length is 1.23 Å. In the nineteenth O site, O is bonded in an L-shaped geometry to one Ca and one O atom. In the twentieth O site, O is bonded in a single-bond geometry to one Ca atom.