Materials Data on Ba2Y(CuO2)4 by Materials Project

Abstract

YBa2Cu4O8 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–3.05 Å. Y3+ is bonded in a linear geometry to two equivalent O2- atoms. Both Y–O bond lengths are 2.18 Å. There are two inequivalent Cu+2.25+ sites. In the first Cu+2.25+ site, Cu+2.25+ is bonded to five O2- atoms to form corner-sharing CuO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.99–2.16 Å. In the second Cu+2.25+ site, Cu+2.25+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.87–1.91 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ba2+ and two Cu+2.25+ atoms to form distorted OBa4Cu2 octahedra that share corners with four equivalent OBa4Cu2 octahedra, corners with four equivalent OBa2YCu2 trigonal bipyramids, edges with four equivalent OBa4Cu2 octahedra, and faces with two equivalent OBa2YCu2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 9°. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Cu+2.25+ atoms. In the third O2- site, O2- is bonded to two equivalent Ba2+, one Y3+, and two equivalent Cu+2.25+ atoms to form distorted OBa2YCu2 trigonal bipyramids that share corners with four equivalent OBa4Cu2 octahedra, corners with five equivalent OBa2YCu2 trigonal bipyramids, and faces with two equivalent OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 57°. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to two equivalent Ba2+ and three equivalent Cu+2.25+ atoms.