Materials Data on Na6Sn2O7 by Materials Project

Abstract

Na6Sn2O7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 square pyramids that share a cornercorner with one SnO5 square pyramid, corners with nine NaO5 square pyramids, edges with three equivalent SnO5 square pyramids, and edges with four NaO5 square pyramids. There are a spread of Na–O bond distances ranging from 2.27–2.47 Å. In the second Na1+ site, Na1+ is bonded to five O2- atoms to form NaO5 square pyramids that share corners with four equivalent SnO5 square pyramids, corners with six NaO5 square pyramids, edges with two equivalent SnO5 square pyramids, and edges with five NaO5 square pyramids. There are a spread of Na–O bond distances ranging from 2.32–2.48 Å. In the third Na1+ site, Na1+ is bonded to five O2- atoms to form NaO5 square pyramids that share corners with two equivalent SnO5 square pyramids, corners with nine NaO5 square pyramids, edges with two equivalent SnO5 square pyramids, and edges with four NaO5 square pyramids. There are a spread of Na–O bond distances ranging from 2.27–2.41 Å. Sn4+ is bonded to five O2- atoms to form distorted SnO5 square pyramids that share a cornercorner with one SnO5 square pyramid, corners with seven NaO5 square pyramids, an edgeedge with one SnO5 square pyramid, and edges with seven NaO5 square pyramids. There are a spread of Sn–O bond distances ranging from 2.01–2.22 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Sn4+ atom to form distorted ONa5Sn octahedra that share corners with four equivalent ONa4Sn square pyramids, edges with eight ONa5Sn octahedra, and edges with two equivalent ONa4Sn square pyramids. In the second O2- site, O2- is bonded to four Na1+ and two equivalent Sn4+ atoms to form ONa4Sn2 octahedra that share corners with three equivalent ONa4Sn2 octahedra, corners with three equivalent ONa4Sn square pyramids, edges with seven ONa5Sn octahedra, and edges with two equivalent ONa4Sn square pyramids. The corner-sharing octahedra tilt angles range from 1–21°. In the third O2- site, O2- is bonded to four Na1+ and one Sn4+ atom to form distorted ONa4Sn square pyramids that share corners with eight ONa5Sn octahedra, corners with two equivalent ONa4Sn square pyramids, and edges with five ONa5Sn octahedra. The corner-sharing octahedra tilt angles range from 9–93°. In the fourth O2- site, O2- is bonded to four Na1+ and two equivalent Sn4+ atoms to form ONa4Sn2 octahedra that share corners with six equivalent ONa4Sn2 octahedra, corners with two equivalent ONa4Sn square pyramids, edges with six ONa5Sn octahedra, and edges with two equivalent ONa4Sn square pyramids. The corner-sharing octahedra tilt angles range from 1–21°.