Materials Data on Ca2Al3O8 by Materials Project
Ca2Al3O8 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first 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 2.23–2.46 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 2.29–2.73 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.76–1.80 Å. In the second Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. There is two shorter (1.77 Å) and two longer (1.78 Å) Al–O bond length. There are five inequivalent O sites. In the first O site, O is bonded in a trigonal planar geometry to one Ca and two equivalent Al atoms. In the second O site, O is bonded in a 4-coordinate geometry to three Ca and one O atom. The O–O bond length is 1.33 Å. In the third O site, O is bonded in a trigonal planar geometry to one Ca and two Al atoms. In the fourth O site, O is bonded in a distorted trigonal planar geometry to one Ca and two Al atoms. In the fifth O site, O is bonded in a distorted trigonal non-coplanar geometry to two Ca and one Al atom.