Materials Data on Sr2SmNb(CuO4)2 by Materials Project
Sr2SmNb(CuO4)2 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Sr2+ is bonded in a distorted q6 geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.75–2.85 Å. Sm3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. There are four shorter (2.44 Å) and four longer (2.50 Å) Sm–O bond lengths. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four equivalent NbO6 octahedra and corners with two equivalent CuO5 square pyramids. The corner-sharing octahedral tilt angles are 31°. There are two shorter (1.98 Å) and four longer (2.03 Å) Nb–O bond lengths. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one NbO6 octahedra and corners with four equivalent CuO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.96 Å) and one longer (2.27 Å) Cu–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Sr2+, one Nb5+, and one Cu2+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Sr2+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Sm3+, and two equivalent Cu2+ atoms.