Materials Data on Sr3Ca(CuO2)4 by Materials Project
Sr3Ca(CuO2)4 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are six shorter (2.61 Å) and two longer (2.67 Å) Sr–O bond lengths. In the second Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight O2- atoms. All Sr–O bond lengths are 2.61 Å. Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.52 Å) and four longer (2.61 Å) Ca–O bond lengths. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.93–1.98 Å. In the second Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There is three shorter (1.97 Å) and one longer (1.98 Å) Cu–O bond length. There are five 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 distorted OSr2Ca2Cu2 octahedra that share corners with fourteen OSr2Ca2Cu2 octahedra, edges with four OSr2Ca2Cu2 octahedra, and faces with four OCa4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–65°. In the second O2- site, O2- is bonded to four Sr2+ and two equivalent Cu2+ atoms to form OSr4Cu2 octahedra that share corners with fourteen OSr2Ca2Cu2 octahedra, edges with four OSr2Ca2Cu2 octahedra, and faces with four OSr4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–65°. In the third O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent Cu2+ atoms to form distorted OCa4Cu2 octahedra that share corners with fourteen OSr2Ca2Cu2 octahedra, edges with four equivalent OCa4Cu2 octahedra, and faces with four equivalent OSr2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–64°. In the fourth O2- site, O2- is bonded to four equivalent Sr2+ and two Cu2+ atoms to form OSr4Cu2 octahedra that share corners with fourteen OSr2Ca2Cu2 octahedra, edges with four equivalent OSr4Cu2 octahedra, and faces with four OSr2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–65°. In the fifth O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Cu2+ atoms to form a mixture of corner, edge, and face-sharing OSr4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–65°.