Materials Data on Na6Ti2O7 by Materials Project

Abstract

Na6Ti2O7 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are five inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.40 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share a cornercorner with one NaO4 tetrahedra, corners with four TiO4 tetrahedra, and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.30–2.36 Å. In the third Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with two NaO4 tetrahedra, corners with four TiO4 tetrahedra, and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.28–2.51 Å. In the fourth Na1+ site, Na1+ is bonded in a linear geometry to two O2- atoms. There are one shorter (2.13 Å) and one longer (2.16 Å) Na–O bond lengths. In the fifth Na1+ site, Na1+ is bonded in a distorted trigonal planar geometry to three O2- atoms. There are two shorter (2.27 Å) and one longer (2.31 Å) Na–O bond lengths. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to four O2- atoms to form TiO4 tetrahedra that share corners with six NaO4 tetrahedra. There is one shorter (1.83 Å) and three longer (1.85 Å) Ti–O bond length. In the second Ti4+ site, Ti4+ is bonded to four O2- atoms to form TiO4 tetrahedra that share corners with two TiO4 tetrahedra and corners with four NaO4 tetrahedra. There are a spread of Ti–O bond distances ranging from 1.80–1.89 Å. In the third Ti4+ site, Ti4+ is bonded to four O2- atoms to form TiO4 tetrahedra that share a cornercorner with one TiO4 tetrahedra and corners with six NaO4 tetrahedra. There is three shorter (1.82 Å) and one longer (1.90 Å) Ti–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Ti4+ atom. In the second O2- site, O2- is bonded to three Na1+ and one Ti4+ atom to form a mixture of distorted corner and edge-sharing ONa3Ti tetrahedra. In the third O2- site, O2- is bonded to two equivalent Na1+ and two Ti4+ atoms to form distorted corner-sharing ONa2Ti2 tetrahedra. In the fourth O2- site, O2- is bonded to three Na1+ and one Ti4+ atom to form corner-sharing ONa3Ti tetrahedra. In the fifth O2- site, O2- is bonded to three Na1+ and one Ti4+ atom to form a mixture of distorted corner and edge-sharing ONa3Ti tetrahedra. In the sixth O2- site, O2- is bonded to three Na1+ and one Ti4+ atom to form a mixture of distorted corner and edge-sharing ONa3Ti tetrahedra. In the seventh O2- site, O2- is bonded to three Na1+ and one Ti4+ atom to form distorted ONa3Ti tetrahedra that share corners with six ONa2Ti2 tetrahedra and an edgeedge with one ONa3Ti tetrahedra. In the eighth O2- site, O2- is bonded in a linear geometry to two equivalent Ti4+ atoms.