Materials Data on KAl2Si4O11 by Materials Project
KAl2Si4O11 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 2.98–3.31 Å. Al is bonded to five O atoms to form AlO5 trigonal bipyramids that share corners with four SiO4 tetrahedra, a cornercorner with one AlO5 trigonal bipyramid, and edges with two equivalent AlO5 trigonal bipyramids. There are a spread of Al–O bond distances ranging from 1.69–1.97 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 three equivalent SiO4 tetrahedra and corners with two equivalent AlO5 trigonal bipyramids. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three equivalent SiO4 tetrahedra and corners with two equivalent AlO5 trigonal bipyramids. There are a spread of Si–O bond distances ranging from 1.65–1.67 Å. There are six inequivalent O sites. In the first O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent K and two Si atoms. 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 distorted trigonal planar geometry to two equivalent Al and one Si atom. In the fourth O site, O is bonded in a linear geometry to two equivalent Al atoms. In the fifth O site, O is bonded in a distorted trigonal planar geometry to two equivalent Al and one Si atom. In the sixth O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent K and two Si atoms.