Materials Data on Ba4Sm2Cu2O9 by Materials Project

Abstract

Sm2Ba4Cu2O9 crystallizes in the tetragonal P-4n2 space group. The structure is three-dimensional. Ba2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.65–2.96 Å. Sm3+ is bonded to seven O2- atoms to form distorted edge-sharing SmO7 hexagonal pyramids. There are a spread of Sm–O bond distances ranging from 2.25–2.50 Å. Cu2+ is bonded in a distorted rectangular see-saw-like geometry to five O2- atoms. There are a spread of Cu–O bond distances ranging from 1.95–2.73 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ba2+, two equivalent Sm3+, and one Cu2+ atom to form distorted OBa3Sm2Cu octahedra that share corners with ten OBa3Sm2Cu octahedra, a cornercorner with one OBa4 trigonal pyramid, edges with three equivalent OBa3Sm2Cu octahedra, an edgeedge with one OBa4 trigonal pyramid, and faces with two equivalent OBa2Sm2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 5–65°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Ba2+, one Sm3+, and one Cu2+ atom. In the third O2- site, O2- is bonded to two equivalent Ba2+, two equivalent Sm3+, and two equivalent Cu2+ atoms to form distorted OBa2Sm2Cu2 octahedra that share corners with eight OBa2Sm2Cu2 octahedra, corners with two equivalent OBa4 trigonal pyramids, an edgeedge with one OBa2Sm2Cu2 octahedra, and faces with four equivalent OBa3Sm2Cu octahedra. The corner-sharing octahedra tilt angles range from 6–65°. In the fourth O2- site, O2- is bonded to four equivalent Ba2+ atoms to form distorted OBa4 trigonal pyramids that share corners with eight OBa2Sm2Cu2 octahedra and edges with four equivalent OBa3Sm2Cu octahedra. The corner-sharing octahedra tilt angles range from 43–71°.