Materials Data on Ca2Al4Si8O33 by Materials Project

Abstract

(CaAl2(SiO4)4)4O2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional and consists of two water molecules and one CaAl2(SiO4)4 framework. In the CaAl2(SiO4)4 framework, Ca is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.98 Å. Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.73–1.80 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share 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 second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Al, and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the third O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the sixth O site, O is bonded in an L-shaped geometry to two equivalent O atoms. Both O–O bond lengths are 1.49 Å. In the seventh O site, O is bonded in a trigonal non-coplanar geometry to one Ca and two equivalent O atoms. In the eighth O site, O is bonded in a single-bond geometry to one Ca atom. In the ninth O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the tenth O site, O is bonded in a 3-coordinate geometry to one Ca, one Al, and one Si atom.