Materials Data on Na2Ti3O7 by Materials Project

Na2Ti3O7 is Pb (Zr_0.50 Ti_0.48) O_3-like structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two 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 2.49–2.76 Å. In the second Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–3.00 Å. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 10–26°. There are a spread of Ti–O bond distances ranging from 1.79–2.20 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 10–28°. There are a spread of Ti–O bond distances ranging from 1.74–2.28 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 32°. There are a spread of Ti–O bond distances ranging from 1.81–2.21 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ti4+ atoms to form distorted OTi4 trigonal pyramids that share corners with three equivalent ONa3Ti2 trigonal bipyramids, corners with two equivalent OTi4 trigonal pyramids, and edges with two equivalent OTi4 trigonal pyramids. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and three Ti4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+ and four Ti4+ atoms. In the fourth O2- site, O2- is bonded to three equivalent Na1+ and two Ti4+ atoms to form distorted ONa3Ti2 trigonal bipyramids that share corners with two equivalent ONa3Ti2 trigonal bipyramids, corners with three equivalent OTi4 trigonal pyramids, and edges with two equivalent ONa3Ti2 trigonal bipyramids. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Ti4+ atom. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+ and two Ti4+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+ and two Ti4+ atoms.