Materials Data on KMg3(SiO3)4 by Materials Project

Abstract

KMg3(SiO3)4 crystallizes in the trigonal P3_112 space group. The structure is three-dimensional. K is bonded in a distorted hexagonal planar geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.68–3.03 Å. There are three inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.98–2.17 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.98–2.17 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.05–2.12 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 MgO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–57°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–58°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. There are six inequivalent O sites. In the first O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom. In the second O site, O is bonded in a 2-coordinate geometry to one K and two Si atoms. In the third O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom. In the fourth O site, O is bonded in a distorted trigonal non-coplanar geometry to one K and two Si atoms. In the fifth O site, O is bonded in a 2-coordinate geometry to one K and two Si atoms. In the sixth O site, O is bonded in a distorted trigonal non-coplanar geometry to three Mg atoms.