Materials Data on Na4Si3(SnO6)2 by Materials Project
Na4Si3(SnO6)2 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.48 Å. In the second Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.51–3.00 Å. Sn4+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with six equivalent SiO4 tetrahedra. There are three shorter (2.04 Å) and three longer (2.10 Å) Sn–O bond lengths. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent SnO6 octahedra. The corner-sharing octahedra tilt angles range from 31–39°. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+, one Sn4+, and one Si4+ atom. In the second O2- site, O2- is bonded to three Na1+, one Sn4+, and one Si4+ atom to form a mixture of distorted corner, edge, and face-sharing ONa3SiSn trigonal bipyramids.