Materials Data on Na6Sn2S7 by Materials Project
Na6Sn2S7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Na–S bond distances ranging from 2.88–3.52 Å. In the second Na1+ site, Na1+ is bonded in a 4-coordinate geometry to six S2- atoms. There are a spread of Na–S bond distances ranging from 2.90–3.46 Å. In the third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four S2- atoms. There are two shorter (2.79 Å) and two longer (2.84 Å) Na–S bond lengths. In the fourth Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with two equivalent SnS4 tetrahedra and edges with two equivalent SnS4 tetrahedra. There are a spread of Na–S bond distances ranging from 2.85–3.10 Å. Sn4+ is bonded to four S2- atoms to form SnS4 tetrahedra that share a cornercorner with one NaS6 octahedra, a cornercorner with one SnS4 tetrahedra, and an edgeedge with one NaS6 octahedra. The corner-sharing octahedral tilt angles are 23°. There are a spread of Sn–S bond distances ranging from 2.39–2.47 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to five Na1+ and one Sn4+ atom. In the second S2- site, S2- is bonded to five Na1+ and one Sn4+ atom to form a mixture of edge and corner-sharing SNa5Sn octahedra. The corner-sharing octahedral tilt angles are 0°. In the third S2- site, S2- is bonded in a 6-coordinate geometry to five Na1+ and one Sn4+ atom. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to four Na1+ and two equivalent Sn4+ atoms.