Materials Data on BaEr2CuO5 by Materials Project
Er2BaCuO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.63–3.28 Å. There are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to seven O2- atoms to form distorted ErO7 pentagonal bipyramids that share corners with four equivalent ErO7 pentagonal bipyramids, edges with three equivalent ErO7 pentagonal bipyramids, edges with two equivalent CuO5 square pyramids, a faceface with one ErO7 pentagonal bipyramid, and a faceface with one CuO5 square pyramid. There are a spread of Er–O bond distances ranging from 2.28–2.37 Å. In the second Er3+ site, Er3+ is bonded to seven O2- atoms to form distorted ErO7 pentagonal bipyramids that share corners with five equivalent CuO5 square pyramids, edges with five ErO7 pentagonal bipyramids, an edgeedge with one CuO5 square pyramid, and a faceface with one ErO7 pentagonal bipyramid. There are a spread of Er–O bond distances ranging from 2.26–2.38 Å. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share corners with five equivalent ErO7 pentagonal bipyramids, edges with three ErO7 pentagonal bipyramids, and a faceface with one ErO7 pentagonal bipyramid. There are a spread of Cu–O bond distances ranging from 1.99–2.31 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ba2+, two Er3+, and one Cu2+ atom to form a mixture of distorted edge and corner-sharing OBa3Er2Cu octahedra. The corner-sharing octahedral tilt angles are 5°. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, three Er3+, and one Cu2+ atom. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, three Er3+, and one Cu2+ atom.