DOI: 10.17188/1653115
title: Materials Data on Na16Ti7(SiO5)8 by Materials Project

description: Na16Ti7(SiO5)8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are six inequivalent Na sites. In the first Na site, Na is bonded to six O atoms to form NaO6 octahedra that share corners with two NaO6 octahedra, a cornercorner with one TiO5 square pyramid, corners with four SiO4 tetrahedra, a cornercorner with one TiO5 trigonal bipyramid, an edgeedge with one NaO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one TiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 40–45°. There are a spread of Na–O bond distances ranging from 2.39–2.53 Å. In the second Na site, Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with two NaO6 octahedra, corners with four SiO4 tetrahedra, a cornercorner with one TiO5 trigonal bipyramid, an edgeedge with one NaO6 octahedra, an edgeedge with one TiO5 square pyramid, and an edgeedge with one TiO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 45°. There are a spread of Na–O bond distances ranging from 2.22–2.69 Å. In the third Na site, Na is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Na–O bond distances ranging from 2.27–2.50 Å. In the fourth Na site, Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.27–2.69 Å. In the fifth Na site, Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with four SiO4 tetrahedra, corners with two equivalent TiO5 trigonal bipyramids, edges with four NaO6 octahedra, and edges with two equivalent TiO5 trigonal bipyramids. There are two shorter (2.51 Å) and four longer (2.57 Å) Na–O bond lengths. In the sixth Na site, Na is bonded in a distorted hexagonal planar geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.38–2.70 Å. There are three inequivalent Ti sites. In the first Ti site, Ti is bonded to five O atoms to form distorted TiO5 trigonal bipyramids that share corners with three NaO6 octahedra, corners with four SiO4 tetrahedra, and edges with three NaO6 octahedra. The corner-sharing octahedra tilt angles range from 66–69°. There are a spread of Ti–O bond distances ranging from 1.72–2.02 Å. In the second Ti site, Ti is bonded to five O atoms to form distorted TiO5 square pyramids that share corners with two equivalent NaO6 octahedra, corners with four SiO4 tetrahedra, and edges with two equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 73°. There are a spread of Ti–O bond distances ranging from 1.71–2.02 Å. In the third Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with four equivalent NaO6 octahedra. There is two shorter (1.92 Å) and four longer (2.02 Å) Ti–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 six NaO6 octahedra, corners with two equivalent TiO5 square pyramids, and corners with two equivalent TiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 61–74°. All Si–O bond lengths are 1.65 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with six NaO6 octahedra, corners with two equivalent TiO5 square pyramids, and corners with two equivalent TiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 60–71°. All Si–O bond lengths are 1.65 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, corners with four NaO6 octahedra, and corners with two equivalent TiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 42–70°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to two Na and one Si atom. In the second O site, O is bonded in a distorted rectangular see-saw-like geometry to two Na, one Ti, and one Si atom. In the third O site, O is bonded in a 4-coordinate geometry to two Na, one Ti, and one Si atom. In the fourth O site, O is bonded in a 4-coordinate geometry to two Na, one Ti, and one Si atom. In the fifth O site, O is bonded in a 1-coordinate geometry to four Na and one Ti atom. In the sixth O site, O is bonded to two Na, one Ti, and one Si atom to form distorted corner-sharing ONa2TiSi tetrahedra. In the seventh O site, O is bonded in a distorted rectangular see-saw-like geometry to two Na, one Ti, and one Si atom. In the eighth O site, O is bonded in a distorted rectangular see-saw-like geometry to two Na, one Ti, and one Si atom. In the ninth O site, O is bonded in a distorted rectangular see-saw-like geometry to two Na, one Ti, and one Si atom. In the tenth O site, O is bonded in a 1-coordinate geometry to three Na and one Ti atom. In the eleventh O site, O is bonded in a 5-coordinate geometry to four Na and one Ti atom.