Materials Data on KMg3Al(SiO4)3 by Materials Project
KMg3Al(SiO4)3 crystallizes in the triclinic P1 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 3.02–3.34 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 a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.17 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.24 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with three SiO4 tetrahedra, and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.20 Å. Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–63°. There is three shorter (1.74 Å) and one longer (1.77 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 corners with three MgO6 octahedra and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Si–O bond distances ranging from 1.62–1.66 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 54–58°. There is one shorter (1.62 Å) and three 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 MgO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–57°. There is one shorter (1.62 Å) and three longer (1.67 Å) Si–O bond length. There are twelve inequivalent O sites. In the first O site, O is bonded in a 2-coordinate 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, one Al, and one Si atom. In the third O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K and two Si atoms. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K and two Si atoms. In the fifth O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. In the sixth O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. In the seventh O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K, one Al, and one Si atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K and two Si atoms. In the ninth O site, O is bonded in a distorted tetrahedral geometry to three Mg and one Al atom. In the tenth O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom. In the eleventh O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom. In the twelfth O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom.