Materials Data on Sr2YTlFe2O7 by Materials Project

Abstract

Sr2YFe2TlO7 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Sr2+ is bonded to five O2- atoms to form distorted SrO5 square pyramids that share corners with five equivalent SrO5 square pyramids, corners with four equivalent FeO5 trigonal bipyramids, edges with four equivalent TlO6 octahedra, and edges with four equivalent SrO5 square pyramids. There are one shorter (2.46 Å) and four longer (2.75 Å) Sr–O bond lengths. Y3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Y–O bond lengths are 2.40 Å. Fe3+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share a cornercorner with one TlO6 octahedra, corners with four equivalent SrO5 square pyramids, and corners with four equivalent FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 0°. There is one shorter (1.91 Å) and four longer (2.00 Å) Fe–O bond length. Tl1+ is bonded to six O2- atoms to form TlO6 octahedra that share corners with four equivalent TlO6 octahedra, corners with two equivalent FeO5 trigonal bipyramids, edges with four equivalent TlO6 octahedra, and edges with eight equivalent SrO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.67 Å) and four longer (2.74 Å) Tl–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Y3+ and two equivalent Fe3+ atoms. In the second O2- site, O2- is bonded to four equivalent Sr2+, one Fe3+, and one Tl1+ atom to form a mixture of distorted edge and corner-sharing OSr4TlFe octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the third O2- site, O2- is bonded to two equivalent Sr2+ and four equivalent Tl1+ atoms to form OSr2Tl4 octahedra that share corners with four equivalent OSr2Tl4 octahedra and edges with twelve OSr4TlFe octahedra. The corner-sharing octahedral tilt angles are 0°.