Materials Data on KMg3AlSi3O11F by Materials Project

Abstract

KMg3AlSi3O11F crystallizes in the monoclinic Cc space group. The structure is three-dimensional. K is bonded in a 12-coordinate geometry to twelve O atoms. There are a spread of K–O bond distances ranging from 3.01–3.44 Å. There are three inequivalent Mg sites. In the first Mg site, Mg is bonded to five O and one F atom to form MgO5F octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six MgO5F octahedra. There are a spread of Mg–O bond distances ranging from 2.05–2.15 Å. The Mg–F bond length is 2.08 Å. In the second Mg site, Mg is bonded to five O and one F atom to form MgO5F octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six MgO5F octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.13 Å. The Mg–F bond length is 2.09 Å. In the third Mg site, Mg is bonded to five O and one F atom to form MgO5F octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six MgO5F octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.16 Å. The Mg–F bond length is 2.02 Å. Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with three MgO5F octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–62°. There are a spread of Al–O bond distances ranging from 1.73–1.77 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO5F octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–58°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO5F octahedra and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–59°. There is three shorter (1.62 Å) and one longer (1.67 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO5F octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–58°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K, one Al, and one Si atom. In the second O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K and two Si atoms. In the third O site, O is bonded in a 2-coordinate 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 equivalent K and two Si atoms. In the fifth O site, O is bonded in a 2-coordinate geometry to two equivalent K, one Al, and one Si atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to two equivalent K and two Si atoms. In the seventh O site, O is bonded to three Mg and one Al atom to form distorted corner-sharing OMg3Al tetrahedra. In the eighth O site, O is bonded in a distorted rectangular see-saw-like geometry to three Mg and one Si atom. In the ninth O site, O is bonded to three Mg and one Si atom to form distorted corner-sharing OMg3Si trigonal pyramids. In the tenth O site, O is bonded in a distorted rectangular see-saw-like geometry to three Mg and one Si atom. In the eleventh O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. F is bonded in a distorted trigonal non-coplanar geometry to three Mg atoms.