Materials Data on KNa3Al4(SiO4)4 by Materials Project

Abstract

KNa3Al4Si4O16 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. K1+ is bonded in a distorted pentagonal pyramidal geometry to six O2- atoms. There are three shorter (2.67 Å) and three longer (2.73 Å) K–O bond lengths. Na1+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.32–2.83 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra. There is one shorter (1.74 Å) and three longer (1.75 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Al–O bond distances ranging from 1.75–1.83 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.64 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Si–O bond distances ranging from 1.63–1.74 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, one Si4+, and one O2- atom. The O–O bond length is 1.50 Å. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Na1+, one Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to three equivalent Na1+, one Al3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+, one Al3+, and one O2- atom.