Materials Data on KAl3(SiO4)3 by Materials Project

KAl3(SiO4)3 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.71–3.23 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form distorted AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with three equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.02 Å. In the second Al site, Al is bonded to six O atoms to form distorted AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with three equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.04 Å. In the third Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–57°. There is two shorter (1.75 Å) and two longer (1.76 Å) Al–O bond length. 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 two AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–55°. 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 two AlO6 octahedra and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–54°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. There are twelve inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to one K, one Al, and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to one K and two Si atoms. In the third O site, O is bonded in a trigonal planar geometry to two Al and one Si atom. In the fourth O site, O is bonded in a distorted trigonal planar geometry to two Al and one Si atom. In the fifth O site, O is bonded in a 2-coordinate geometry to one K, one Al, and one Si atom. In the sixth O site, O is bonded in a distorted bent 120 degrees geometry to one K and two Si atoms. In the seventh O site, O is bonded in a 2-coordinate geometry to two Al and one O atom. The O–O bond length is 1.58 Å. In the eighth O site, O is bonded in a 2-coordinate geometry to two Al and one O atom. In the ninth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the tenth O site, O is bonded in a distorted trigonal planar geometry to two Al and one Si atom. In the eleventh O site, O is bonded in a 2-coordinate geometry to one K, one Al, and one Si atom. In the twelfth O site, O is bonded in a distorted bent 120 degrees geometry to one K and two Si atoms.