Materials Data on SrNd2(CuO3)2 by Materials Project
Nd2SrCu2O6 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Sr2+ is bonded in a 1-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.41–2.81 Å. There are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.44 Å) and four longer (2.54 Å) Nd–O bond lengths. In the second Nd3+ site, Nd3+ is bonded in a 1-coordinate geometry to nine O2- atoms. There are a spread of Nd–O bond distances ranging from 2.22–2.75 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to five O2- atoms to form corner-sharing CuO5 square pyramids. There are four shorter (1.95 Å) and one longer (2.29 Å) Cu–O bond lengths. In the second Cu2+ site, Cu2+ is bonded to five O2- atoms to form corner-sharing CuO5 square pyramids. There are four shorter (1.93 Å) and one longer (2.17 Å) Cu–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Nd3+, and two equivalent Cu2+ atoms. In the second O2- site, O2- is bonded to four Nd3+ and two equivalent Cu2+ atoms to form a mixture of distorted edge, face, and corner-sharing ONd4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 6–54°. In the third O2- site, O2- is bonded to four equivalent Sr2+, one Nd3+, and one Cu2+ atom to form distorted OSr4NdCu octahedra that share corners with eight ONd4Cu2 octahedra and edges with eight OSr4NdCu octahedra. The corner-sharing octahedra tilt angles range from 22–45°. In the fourth O2- site, O2- is bonded to one Sr2+, four equivalent Nd3+, and one Cu2+ atom to form distorted OSrNd4Cu octahedra that share corners with twelve ONd4Cu2 octahedra, edges with eight OSr4NdCu octahedra, and faces with four equivalent ONd4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 15–54°.