Materials Data on Na2Ti2Si4O13 by Materials Project

Na2Ti2Si4O13 is Esseneite-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.98 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent TiO6 octahedra. There are a spread of Ti–O bond distances ranging from 1.82–2.18 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 corners with three equivalent TiO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 32–55°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 31°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Na1+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+ and two equivalent Ti4+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ti4+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+, two equivalent Ti4+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ti4+, and one Si4+ atom.