DOI: 10.17188/1722599
title: Materials Data on Ca2Al3Si3O14 by Materials Project

description: Ca2Al3Si3O14 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to seven O atoms to form distorted CaO7 pentagonal bipyramids that share corners with five SiO4 tetrahedra, edges with four AlO6 octahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.54 Å. In the second Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.24–2.73 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, edges with two equivalent AlO6 octahedra, and an edgeedge with one CaO7 pentagonal bipyramid. There are a spread of Al–O bond distances ranging from 1.86–2.03 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra, edges with two equivalent AlO6 octahedra, and edges with two equivalent CaO7 pentagonal bipyramids. There are a spread of Al–O bond distances ranging from 1.83–2.10 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four equivalent AlO6 octahedra, a cornercorner with one SiO4 tetrahedra, and an edgeedge with one CaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with six AlO6 octahedra and corners with two equivalent CaO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 48–58°. There is three shorter (1.65 Å) and one longer (1.66 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent AlO6 octahedra, corners with three equivalent CaO7 pentagonal bipyramids, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Si–O bond distances ranging from 1.60–1.69 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a water-like geometry to two equivalent Al atoms. In the second O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Al, and one Si atom. In the third O site, O is bonded in a water-like geometry to two equivalent Al atoms. In the fourth O site, O is bonded in a trigonal non-coplanar geometry to one Ca and two equivalent Al atoms. In the fifth O site, O is bonded in a 3-coordinate geometry to one Ca and two Si atoms. In the sixth O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom. In the seventh O site, O is bonded in a 4-coordinate geometry to two Ca, one Al, and one Si atom. In the eighth O site, O is bonded in a bent 150 degrees geometry to one Ca and one Si atom. In the ninth O site, O is bonded in a 3-coordinate geometry to two equivalent Al and one Si atom. In the tenth O site, O is bonded in a trigonal planar geometry to one Ca, one Al, and one Si atom. In the eleventh O site, O is bonded in a 4-coordinate geometry to one Ca, two equivalent Al, and one Si atom.