Materials Data on Na6V2O7 by Materials Project
Na6V2O7 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 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.24–3.06 Å. In the second 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 2.34–2.70 Å. In the third Na1+ site, Na1+ is bonded to five O2- atoms to form NaO5 trigonal bipyramids that share corners with three VO4 tetrahedra and an edgeedge with one VO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.32–2.61 Å. In the fourth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–3.00 Å. In the fifth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–3.09 Å. In the sixth Na1+ site, Na1+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.25–2.42 Å. There are two inequivalent V4+ sites. In the first V4+ site, V4+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, a cornercorner with one NaO5 trigonal bipyramid, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of V–O bond distances ranging from 1.78–1.87 Å. In the second V4+ site, V4+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra and corners with two equivalent NaO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.78–1.90 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 V4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and two V4+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one V4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to four Na1+ and one V4+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one V4+ atom. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to five Na1+ and one V4+ atom. In the seventh O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one V4+ atom.