DOI: 10.17188/1752729
title: Materials Data on Na2Ti2Si2H2O9 by Materials Project

description: Na2Ti2Si2H2O9 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Na2Ti2Si2H2O9 sheet oriented in the (0, 0, 1) direction. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–3.00 Å. In the second Na1+ site, Na1+ is bonded to one H1+ and seven O2- atoms to form NaHO7 hexagonal bipyramids that share corners with two equivalent NaHO7 hexagonal bipyramids, corners with two TiO6 octahedra, edges with four SiO4 tetrahedra, and edges with two equivalent TiHO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–55°. The Na–H bond length is 2.49 Å. There are a spread of Na–O bond distances ranging from 2.50–2.73 Å. In the third Na1+ site, Na1+ is bonded to one H1+ and seven O2- atoms to form NaHO7 hexagonal bipyramids that share corners with two equivalent NaHO7 hexagonal bipyramids, corners with two TiO6 octahedra, edges with four SiO4 tetrahedra, and edges with two equivalent TiHO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–55°. The Na–H bond length is 2.53 Å. There are a spread of Na–O bond distances ranging from 2.49–2.75 Å. In the fourth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.98 Å. There are four inequivalent Ti3+ sites. In the first Ti3+ site, Ti3+ is bonded to one H1+ and five O2- atoms to form distorted TiHO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with four SiO4 tetrahedra, and edges with two equivalent NaHO7 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 44°. The Ti–H bond length is 2.44 Å. There are a spread of Ti–O bond distances ranging from 1.80–1.96 Å. In the second Ti3+ site, Ti3+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two NaHO7 hexagonal bipyramids, corners with three SiO4 tetrahedra, a cornercorner with one TiHO5 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. In the third Ti3+ site, Ti3+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two NaHO7 hexagonal bipyramids, corners with three SiO4 tetrahedra, a cornercorner with one TiHO5 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. In the fourth Ti3+ site, Ti3+ is bonded to one H1+ and five O2- atoms to form distorted TiHO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with four SiO4 tetrahedra, and edges with two equivalent NaHO7 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. The Ti–H bond length is 2.45 Å. There are a spread of Ti–O bond distances ranging from 1.80–1.95 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiHO5 trigonal bipyramids, and edges with two equivalent NaHO7 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 51°. There are a spread of Si–O bond distances ranging from 1.62–1.66 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, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiHO5 trigonal bipyramids, and edges with two equivalent NaHO7 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 51°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two TiO6 octahedra, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiHO5 trigonal bipyramids, and edges with two equivalent NaHO7 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 fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two TiO6 octahedra, a cornercorner with one SiO4 tetrahedra, corners with two equivalent TiHO5 trigonal bipyramids, and edges with two equivalent NaHO7 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 four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one Na1+ atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Ti3+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one Na1+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one Ti3+ atom. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ti3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ti3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Ti3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Ti3+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+, one Ti3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Ti3+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ti3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ti3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ti3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ti3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ti3+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two Ti3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ti3+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Ti3+ atoms. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two Ti3+, and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two Si4+ atoms. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+, one Ti3+, and one Si4+ atom. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two Si4+ atoms.