Materials Data on CaAl2O12 by Materials Project

Abstract

CaO7Al2O3O2 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional and consists of two hexaoxane molecules and one CaO7Al2O3 framework. In the CaO7Al2O3 framework, Ca is bonded in a 5-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.12–2.94 Å. Al is bonded to five O atoms to form distorted edge-sharing AlO5 trigonal bipyramids. There are a spread of Al–O bond distances ranging from 1.70–2.14 Å. There are six inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Ca and one Al atom. In the second O site, O is bonded in a trigonal planar geometry to one Ca and two equivalent O atoms. Both O–O bond lengths are 1.39 Å. In the third O site, O is bonded in a 1-coordinate geometry to one Ca, one Al, and one O atom. The O–O bond length is 1.41 Å. In the fourth O site, O is bonded in a distorted trigonal planar geometry to one Ca and two equivalent O atoms. Both O–O bond lengths are 1.47 Å. In the fifth O site, O is bonded in a 2-coordinate geometry to two equivalent Al and one O atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Al and one O atom.