Materials Data on KAl2Si4(HO6)2 by Materials Project
KAl2Si4(HO6)2 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 3.02–3.31 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 1.91–1.99 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 52–56°. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. 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 52–56°. There is two shorter (1.65 Å) and two longer (1.66 Å) Si–O bond length. H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 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 distorted trigonal non-coplanar geometry to two equivalent Al and one H atom. 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 trigonal planar geometry to two equivalent Al and one Si atom. 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 distorted bent 150 degrees geometry to one K and two Si atoms.