DOI: 10.17188/1301899
title: Materials Data on Na6Sn2O7 by Materials Project

description: Na6Sn2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with four NaO4 tetrahedra, corners with four SnO4 tetrahedra, a cornercorner with one NaO4 trigonal pyramid, edges with two NaO4 tetrahedra, and an edgeedge with one NaO4 trigonal pyramid. There are a spread of Na–O bond distances ranging from 2.21–2.36 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four NaO4 tetrahedra, corners with four SnO4 tetrahedra, corners with three equivalent NaO4 trigonal pyramids, and edges with two NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.27–2.41 Å. In the third Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four SnO4 tetrahedra, corners with eight NaO4 tetrahedra, a cornercorner with one NaO4 trigonal pyramid, and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.31–2.45 Å. In the fourth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four SnO4 tetrahedra, corners with five NaO4 tetrahedra, a cornercorner with one NaO4 trigonal pyramid, and an edgeedge with one SnO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.25–2.73 Å. In the fifth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four SnO4 tetrahedra, corners with five NaO4 tetrahedra, a cornercorner with one NaO4 trigonal pyramid, edges with two NaO4 tetrahedra, and an edgeedge with one NaO4 trigonal pyramid. There are a spread of Na–O bond distances ranging from 2.33–2.50 Å. In the sixth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 trigonal pyramids that share corners with four SnO4 tetrahedra, corners with seven NaO4 tetrahedra, and edges with two NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.25–2.48 Å. There are two inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to four O2- atoms to form SnO4 tetrahedra that share a cornercorner with one SnO4 tetrahedra, corners with twelve NaO4 tetrahedra, and a cornercorner with one NaO4 trigonal pyramid. There are a spread of Sn–O bond distances ranging from 1.97–2.07 Å. In the second Sn4+ site, Sn4+ is bonded to four O2- atoms to form SnO4 tetrahedra that share a cornercorner with one SnO4 tetrahedra, corners with eight NaO4 tetrahedra, corners with three equivalent NaO4 trigonal pyramids, and an edgeedge with one NaO4 tetrahedra. There are a spread of Sn–O bond distances ranging from 1.96–2.08 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+ and one Sn4+ atom to form ONa3Sn tetrahedra that share a cornercorner with one ONa3Sn tetrahedra and corners with three equivalent ONa2Sn2 trigonal pyramids. In the second O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the fourth O2- site, O2- is bonded to three Na1+ and one Sn4+ atom to form ONa3Sn tetrahedra that share a cornercorner with one ONa3Sn tetrahedra, a cornercorner with one ONa2Sn2 trigonal pyramid, and an edgeedge with one ONa2Sn2 trigonal pyramid. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the sixth O2- site, O2- is bonded to two equivalent Na1+ and two Sn4+ atoms to form distorted ONa2Sn2 trigonal pyramids that share corners with four ONa3Sn tetrahedra, corners with two equivalent ONa2Sn2 trigonal pyramids, and an edgeedge with one ONa3Sn tetrahedra. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom.