Materials Data on KAlSiO4 by Materials Project

Abstract

KAlSiO4 crystallizes in the trigonal P31c space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.98–3.03 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent SiO4 tetrahedra. There is one shorter (1.75 Å) and three longer (1.76 Å) Al–O bond length. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent AlO4 tetrahedra. There is one shorter (1.63 Å) and three longer (1.64 Å) Si–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to three equivalent K1+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+, one Al3+, and one Si4+ atom.