Materials Data on KAl2(SiO3)4 by Materials Project

Abstract

KAl2(SiO3)4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to ten O atoms. There are a spread of K–O bond distances ranging from 2.91–3.25 Å. Al is bonded to six O atoms to form AlO6 octahedra that share corners with four SiO4 tetrahedra and edges with three equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–1.98 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 AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. There are six 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 bent 150 degrees geometry to one K and two Si atoms. In the third O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent K and two Si atoms. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent K and two Si atoms. In the fifth O site, O is bonded in a trigonal planar geometry to two equivalent Al and one Si atom. In the sixth O site, O is bonded in a trigonal planar geometry to two equivalent Al and one Si atom.