DOI: 10.17188/1680378
title: Materials Data on Na2Ti2Si2O11 by Materials Project

description: Na2Ti2Si2O11 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Na2Ti2Si2O11 sheet oriented in the (0, 0, 1) direction. there are four inequivalent Na sites. In the first Na site, Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share corners with two equivalent NaO8 hexagonal bipyramids, corners with two TiO6 octahedra, edges with four SiO4 tetrahedra, and edges with two equivalent TiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–55°. There are a spread of Na–O bond distances ranging from 2.48–2.73 Å. In the second Na site, Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share corners with two equivalent NaO8 hexagonal bipyramids, corners with two TiO6 octahedra, edges with four SiO4 tetrahedra, and edges with two equivalent TiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–55°. There are a spread of Na–O bond distances ranging from 2.51–2.73 Å. In the third 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 2.30–2.75 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 2.29–2.77 Å. There are four inequivalent Ti sites. In the first Ti site, Ti is bonded to five O atoms to form TiO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with four SiO4 tetrahedra, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. There are a spread of Ti–O bond distances ranging from 1.80–1.95 Å. In the second Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with two NaO8 hexagonal bipyramids, corners with three SiO4 tetrahedra, a cornercorner with one TiO5 trigonal bipyramid, and edges with two equivalent TiO6 octahedra. There are a spread of Ti–O bond distances ranging from 1.82–2.24 Å. In the third Ti site, Ti is bonded to five O atoms to form TiO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with four SiO4 tetrahedra, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. There are a spread of Ti–O bond distances ranging from 1.80–1.95 Å. In the fourth Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with two NaO8 hexagonal bipyramids, corners with three SiO4 tetrahedra, a cornercorner with one TiO5 trigonal bipyramid, and edges with two equivalent TiO6 octahedra. There are a spread of Ti–O bond distances ranging from 1.83–2.24 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiO5 trigonal bipyramids, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There is two shorter (1.62 Å) and two longer (1.66 Å) Si–O bond length. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two TiO6 octahedra, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiO5 trigonal bipyramids, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Si–O bond distances ranging from 1.62–1.68 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, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiO5 trigonal bipyramids, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 51°. There is two shorter (1.62 Å) and two longer (1.66 Å) Si–O bond length. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two TiO6 octahedra, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiO5 trigonal bipyramids, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. There are twenty-two inequivalent O sites. In the first O site, O is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na and two Si atoms. In the second O site, O is bonded in a 4-coordinate geometry to one Na, two 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 bent 120 degrees geometry to one Na and one O atom. The O–O bond length is 1.23 Å. In the fifth O site, O is bonded in a 4-coordinate geometry to one Na, two Ti, and one Si atom. In the sixth O site, O is bonded in a 4-coordinate geometry to two Na and two Ti atoms. In the seventh O site, O is bonded in a 4-coordinate geometry to two Na and two Ti atoms. In the eighth O site, O is bonded in a 2-coordinate geometry to one Na, one Ti, and one Si atom. In the ninth O site, O is bonded in a 3-coordinate geometry to one Na, one Ti, and one Si atom. In the tenth O site, O is bonded in a single-bond geometry to one O atom. In the eleventh O site, O is bonded in a 4-coordinate geometry to two Na and two Ti atoms. In the twelfth O site, O is bonded in a 4-coordinate geometry to two Na, one Ti, and one Si atom. In the thirteenth O site, O is bonded in a 4-coordinate geometry to two Na and two Ti atoms. In the fourteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Na, one Ti, and one Si atom. In the fifteenth O site, O is bonded in a 3-coordinate geometry to one Na, one Ti, and one Si atom. In the sixteenth O site, O is bonded in a 3-coordinate geometry to one Na, one Ti, and one Si atom. In the seventeenth O site, O is bonded in a 3-coordinate geometry to one Na, one Ti, and one Si atom. In the eighteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Na, one Ti, and one Si atom. In the nineteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Na, one Ti, and one Si atom. In the twentieth O site, O is bonded in a 4-coordinate geometry to two equivalent Na and two Si atoms. In the twenty-first O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å. In the twenty-second O site, O is bonded in a bent 120 degrees geometry to one Na and one O atom.