Materials Data on Fe4Si2Sn7O16 by Materials Project

Abstract

FeFe3Si2Sn7O16 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one iron molecule and one Fe3Sn7Si2O16 sheet oriented in the (0, 0, 1) direction. In the Fe3Sn7Si2O16 sheet, Fe+2.50+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with two equivalent SiO4 tetrahedra, corners with four equivalent SnO4 trigonal pyramids, edges with two equivalent SnO6 octahedra, and edges with four equivalent FeO6 octahedra. There are two shorter (2.16 Å) and four longer (2.33 Å) Fe–O bond lengths. There are two inequivalent Sn2+ sites. In the first Sn2+ site, Sn2+ is bonded to four O2- atoms to form distorted SnO4 trigonal pyramids that share a cornercorner with one SnO6 octahedra, corners with two equivalent FeO6 octahedra, corners with two equivalent SiO4 tetrahedra, and edges with two equivalent SnO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 57–65°. There are a spread of Sn–O bond distances ranging from 2.04–2.27 Å. In the second Sn2+ site, Sn2+ is bonded to six equivalent O2- atoms to form SnO6 octahedra that share corners with six equivalent SnO4 trigonal pyramids and edges with six equivalent FeO6 octahedra. All Sn–O bond lengths are 2.14 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent FeO6 octahedra and corners with six equivalent SnO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 68°. There is three shorter (1.63 Å) and one longer (1.67 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Sn2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a trigonal planar geometry to three equivalent Sn2+ atoms. In the third O2- site, O2- is bonded to two equivalent Fe+2.50+ and two Sn2+ atoms to form a mixture of distorted corner and edge-sharing OFe2Sn2 tetrahedra. In the fourth O2- site, O2- is bonded to three equivalent Fe+2.50+ and one Si4+ atom to form a mixture of corner and edge-sharing OFe3Si tetrahedra.