Materials Data on BaSrNdTlCu2O7 by Materials Project
BaSrNdCu2TlO7 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.73–3.03 Å. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.49–2.90 Å. Nd3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.48–2.50 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted corner-sharing CuO5 square pyramids. There are a spread of Cu–O bond distances ranging from 1.95–2.62 Å. In the second Cu2+ site, Cu2+ is bonded to five O2- atoms to form corner-sharing CuO5 square pyramids. There are a spread of Cu–O bond distances ranging from 1.96–2.26 Å. Tl3+ is bonded in a see-saw-like geometry to four O2- atoms. There are a spread of Tl–O bond distances ranging from 2.14–2.37 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, two equivalent Nd3+, and two equivalent Cu2+ atoms. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, two equivalent Nd3+, and two equivalent Cu2+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Nd3+, and two equivalent Cu2+ atoms. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Nd3+, and two equivalent Cu2+ atoms. In the fifth O2- site, O2- is bonded to four equivalent Ba2+, one Cu2+, and one Tl3+ atom to form a mixture of distorted edge and corner-sharing OBa4TlCu octahedra. The corner-sharing octahedra tilt angles range from 18–21°. In the sixth O2- site, O2- is bonded to four equivalent Sr2+, one Cu2+, and one Tl3+ atom to form distorted OSr4TlCu octahedra that share corners with five OBa4TlCu octahedra and edges with four equivalent OSr4TlCu octahedra. The corner-sharing octahedra tilt angles range from 17–18°. In the seventh O2- site, O2- is bonded in a see-saw-like geometry to one Ba2+, one Sr2+, and two equivalent Tl3+ atoms.