Materials Data on BaYCo2O5 by Materials Project

Abstract

YBaCo2O5 crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, faces with four equivalent BaO12 cuboctahedra, faces with four equivalent CoO5 square pyramids, and faces with four equivalent CoO5 trigonal bipyramids. There are a spread of Ba–O bond distances ranging from 2.79–3.09 Å. Y3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are two shorter (2.42 Å) and six longer (2.43 Å) Y–O bond lengths. There are two inequivalent Co+2.50+ sites. In the first Co+2.50+ site, Co+2.50+ is bonded to five O2- atoms to form CoO5 square pyramids that share corners with two equivalent CoO5 square pyramids, corners with three equivalent CoO5 trigonal bipyramids, and faces with four equivalent BaO12 cuboctahedra. There are a spread of Co–O bond distances ranging from 2.00–2.13 Å. In the second Co+2.50+ site, Co+2.50+ is bonded to five O2- atoms to form distorted CoO5 trigonal bipyramids that share corners with three equivalent CoO5 square pyramids, corners with two equivalent CoO5 trigonal bipyramids, and faces with four equivalent BaO12 cuboctahedra. There are a spread of Co–O bond distances ranging from 1.82–2.04 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, two equivalent Y3+, and two equivalent Co+2.50+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, two equivalent Y3+, and two Co+2.50+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, two equivalent Y3+, and two equivalent Co+2.50+ atoms. In the fourth O2- site, O2- is bonded to four equivalent Ba2+ and two Co+2.50+ atoms to form a mixture of distorted edge and corner-sharing OBa4Co2 octahedra. The corner-sharing octahedral tilt angles are 0°.