Materials Data on SrCa2Cu2(BiO4)2 by Materials Project

Abstract

Bi2Ca2SrCu2O8 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. Sr2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.60 Å) and four longer (2.67 Å) Sr–O bond lengths. Ca2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ca–O bond distances ranging from 2.44–3.10 Å. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one BiO5 square pyramid and corners with four equivalent CuO5 square pyramids. There are a spread of Cu–O bond distances ranging from 1.90–2.42 Å. Bi3+ is bonded to five O2- atoms to form distorted BiO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with two equivalent BiO5 square pyramids, and edges with five equivalent BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.05–3.03 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Ca2+, and two equivalent Cu2+ atoms to form a mixture of distorted corner, edge, and face-sharing OSr2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–63°. In the second O2- site, O2- is bonded in a 5-coordinate geometry to one Ca2+ and four equivalent Bi3+ atoms. In the third O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Ca2+, and two equivalent Cu2+ atoms to form a mixture of distorted corner, edge, and face-sharing OSr2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–63°. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Ca2+, one Cu2+, and one Bi3+ atom.