Materials Data on Na4Ti4Si3O22 by Materials Project
Na4Ti4Si3O16(O2)3 crystallizes in the trigonal R3m space group. The structure is three-dimensional and consists of three hexaoxane molecules and one Na4Ti4Si3O16 framework. In the Na4Ti4Si3O16 framework, there are two inequivalent Na sites. In the first Na site, Na is bonded to four O atoms to form distorted NaO4 trigonal pyramids that share corners with six equivalent TiO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–62°. There are one shorter (2.21 Å) and three longer (2.90 Å) Na–O bond lengths. In the second Na site, Na is bonded in a 4-coordinate geometry to four O atoms. There are two shorter (2.38 Å) and two longer (2.68 Å) Na–O bond lengths. There are two inequivalent Ti sites. In the first Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with three equivalent SiO4 tetrahedra and edges with three equivalent TiO6 octahedra. There is three shorter (1.94 Å) and three longer (1.96 Å) Ti–O bond length. In the second Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with three equivalent SiO4 tetrahedra, corners with two equivalent NaO4 trigonal pyramids, and edges with three TiO6 octahedra. There are a spread of Ti–O bond distances ranging from 1.92–2.07 Å. Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four TiO6 octahedra and a cornercorner with one NaO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. There are five inequivalent O sites. In the first O site, O is bonded in a tetrahedral geometry to one Na and three equivalent Ti atoms. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to three Ti atoms. In the third O site, O is bonded in a 4-coordinate geometry to two equivalent Na, one Ti, and one Si atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one Na, one Ti, and one Si atom. In the fifth O site, O is bonded in a 2-coordinate geometry to one Na, one Ti, and one Si atom.