Materials Data on Sr2CaCu2(BiO4)2 by Materials Project

Abstract

Bi2Sr2CaCu2O8 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two Bi2Sr2CaCu2O8 sheets oriented in the (0, 0, 1) direction. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.62–2.84 Å. Ca2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ca–O bond lengths are 2.47 Å. Cu2+ is bonded in a distorted rectangular see-saw-like geometry to five O2- atoms. There are four shorter (1.88 Å) and one longer (2.71 Å) Cu–O bond lengths. Bi3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing BiO5 square pyramids. There are one shorter (2.07 Å) and four longer (2.65 Å) Bi–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to one Sr2+ and four equivalent Bi3+ atoms to form OSrBi4 square pyramids that share corners with four equivalent OSr2Ca2Cu2 octahedra, corners with four equivalent OSrBi4 square pyramids, and edges with four equivalent OSrBi4 square pyramids. The corner-sharing octahedral tilt angles are 46°. In the second O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Ca2+, and two equivalent Cu2+ atoms to form distorted OSr2Ca2Cu2 octahedra that share corners with eight equivalent OSr2Ca2Cu2 octahedra, corners with two equivalent OSrBi4 square pyramids, edges with three equivalent OSr2Ca2Cu2 octahedra, and faces with four equivalent OSr2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–65°. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Sr2+, one Cu2+, and one Bi3+ atom.