Materials Data on Sr2NdTlCu2O7 by Materials Project
Sr2NdCu2TlO7 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–2.87 Å. Nd3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are six shorter (2.48 Å) and two longer (2.49 Å) Nd–O bond lengths. 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 1.94–2.27 Å. Tl3+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are two shorter (2.13 Å) and two longer (2.44 Å) Tl–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 in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Nd3+, and two equivalent Cu2+ atoms. In the third O2- site, O2- is bonded to four equivalent Sr2+, one Cu2+, and one Tl3+ atom to form a mixture of distorted edge and corner-sharing OSr4TlCu octahedra. The corner-sharing octahedra tilt angles range from 15–17°. In the fourth O2- site, O2- is bonded in a see-saw-like geometry to two equivalent Sr2+ and two equivalent Tl3+ atoms.