Materials Data on Na6Ti2O7 by Materials Project

Abstract

Na6Ti2O7 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. there are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.63 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.88 Å. In the third Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with three TiO4 tetrahedra, an edgeedge with one TiO4 tetrahedra, and edges with two equivalent NaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.33–2.71 Å. In the fourth Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with three TiO4 tetrahedra, an edgeedge with one TiO4 tetrahedra, and edges with two equivalent NaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.33–2.76 Å. In the fifth 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 2.27–2.35 Å. In the sixth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.69 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to four O2- atoms to form TiO4 tetrahedra that share a cornercorner with one TiO4 tetrahedra, corners with three NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Ti–O bond distances ranging from 1.80–1.91 Å. In the second Ti4+ site, Ti4+ is bonded to four O2- atoms to form TiO4 tetrahedra that share a cornercorner with one TiO4 tetrahedra, corners with three NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Ti–O bond distances ranging from 1.80–1.91 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Ti4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Ti4+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Ti4+ atom. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Ti4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one Ti4+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one Ti4+ atom. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Ti4+ atom.