Materials Data on Sr2SmTa(CuO4)2 by Materials Project

Abstract

Sr2SmTa(CuO4)2 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form distorted SrO12 cuboctahedra that share corners with eight equivalent SrO12 cuboctahedra, faces with five equivalent SrO12 cuboctahedra, faces with four equivalent TaO6 octahedra, and faces with four equivalent CuO5 square pyramids. There are a spread of Sr–O bond distances ranging from 2.81–3.07 Å. Sm3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Sm–O bond lengths are 2.48 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with four equivalent TaO6 octahedra, corners with two equivalent CuO5 square pyramids, and faces with eight equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is four shorter (1.97 Å) and two longer (1.98 Å) Ta–O bond length. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one TaO6 octahedra, corners with four equivalent CuO5 square pyramids, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.97 Å) and one longer (2.25 Å) Cu–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Sm3+, and two equivalent Cu2+ atoms to form a mixture of distorted corner, edge, and face-sharing OSr2Sm2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–68°. In the second O2- site, O2- is bonded in a linear geometry to four equivalent Sr2+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Sr2+, one Ta5+, and one Cu2+ atom.