Materials Data on Sr2GdCu2HgO7 by Materials Project

Abstract

Sr2GdCu2HgO7 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Sr2+ is bonded in a 5-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.43–2.92 Å. Gd3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Gd–O bond lengths are 2.42 Å. Cu+2.50+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one HgO6 octahedra and corners with four equivalent CuO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.94 Å) and one longer (2.20 Å) Cu–O bond lengths. Hg2+ is bonded to six O2- atoms to form HgO6 octahedra that share corners with four equivalent HgO6 octahedra, corners with two equivalent CuO5 square pyramids, and edges with four equivalent HgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.14 Å) and four longer (2.71 Å) Hg–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Sr2+, one Cu+2.50+, and one Hg2+ atom to form OSr4CuHg octahedra that share corners with five equivalent OSr4CuHg octahedra and edges with eight OSr2Hg4 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Gd3+, and two equivalent Cu+2.50+ atoms. In the third O2- site, O2- is bonded to two equivalent Sr2+ and four equivalent Hg2+ atoms to form a mixture of edge and corner-sharing OSr2Hg4 octahedra. The corner-sharing octahedral tilt angles are 0°.