Materials Data on KAl(SiO3)3 by Materials Project
(KAlSi3O8)2O2 crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one water molecule and one KAlSi3O8 sheet oriented in the (0, 0, 1) direction. In the KAlSi3O8 sheet, K is bonded in a 6-coordinate geometry to six equivalent O atoms. All K–O bond lengths are 2.99 Å. Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There is three shorter (1.72 Å) and one longer (1.73 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 a cornercorner with one SiO4 tetrahedra and corners with three equivalent AlO4 tetrahedra. There is three shorter (1.61 Å) and one longer (1.68 Å) Si–O bond length. In the second Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.63 Å) and three longer (1.66 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three equivalent SiO4 tetrahedra. There is one shorter (1.58 Å) and three longer (1.66 Å) Si–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a linear geometry to one Al and one Si atom. In the second O site, O is bonded in a linear geometry to two Si atoms. In the third O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K, one Al, and one Si atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Si atoms.