Materials Data on Na2Ti9O19 by Materials Project

Na2Ti9O19 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.03 Å) and two longer (2.17 Å) Na–O bond lengths. In the second 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 2.51–2.62 Å. There are nine inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 25°. There are a spread of Ti–O bond distances ranging from 1.85–2.17 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 25°. There are a spread of Ti–O bond distances ranging from 1.85–2.17 Å. In the third Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.74–2.36 Å. In the fourth Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.76–2.33 Å. In the fifth Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.76–2.50 Å. In the sixth Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.74–2.52 Å. In the seventh Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.77–2.37 Å. In the eighth Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.76–2.36 Å. In the ninth Ti4+ site, Ti4+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 11°. There are a spread of Ti–O bond distances ranging from 1.90–2.14 Å. There are nineteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti4+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two Ti4+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+ and two Ti4+ atoms. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to three Ti4+ atoms. In the sixth O2- site, O2- is bonded in a distorted T-shaped geometry to three Ti4+ atoms. In the seventh O2- site, O2- is bonded to four Ti4+ atoms to form a mixture of distorted edge and corner-sharing OTi4 trigonal pyramids. In the eighth O2- site, O2- is bonded to four Ti4+ atoms to form distorted corner-sharing OTi4 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Ti4+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to three Ti4+ atoms. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+ and two Ti4+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two Ti4+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+ and two equivalent Ti4+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+ and three Ti4+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+ and three Ti4+ atoms. In the sixteenth O2- site, O2- is bonded to four Ti4+ atoms to form a mixture of distorted edge and corner-sharing OTi4 tetrahedra. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to four Ti4+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+ and two Ti4+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+ and two Ti4+ atoms.