Materials Data on BaTm2CuO5 by Materials Project

Abstract

Tm2BaCuO5 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 2.64–3.28 Å. There are two inequivalent Tm3+ sites. In the first Tm3+ site, Tm3+ is bonded to seven O2- atoms to form distorted TmO7 pentagonal bipyramids that share corners with five equivalent CuO5 square pyramids, edges with five TmO7 pentagonal bipyramids, an edgeedge with one CuO5 square pyramid, and a faceface with one TmO7 pentagonal bipyramid. There are a spread of Tm–O bond distances ranging from 2.24–2.36 Å. In the second Tm3+ site, Tm3+ is bonded to seven O2- atoms to form distorted TmO7 pentagonal bipyramids that share corners with four equivalent TmO7 pentagonal bipyramids, edges with three equivalent TmO7 pentagonal bipyramids, edges with two equivalent CuO5 square pyramids, a faceface with one TmO7 pentagonal bipyramid, and a faceface with one CuO5 square pyramid. There are a spread of Tm–O bond distances ranging from 2.26–2.36 Å. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share corners with five equivalent TmO7 pentagonal bipyramids, edges with three TmO7 pentagonal bipyramids, and a faceface with one TmO7 pentagonal bipyramid. There are a spread of Cu–O bond distances ranging from 1.99–2.30 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ba2+, two Tm3+, and one Cu2+ atom to form a mixture of distorted edge and corner-sharing OBa3Tm2Cu octahedra. The corner-sharing octahedral tilt angles are 6°. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, three Tm3+, and one Cu2+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, three Tm3+, and one Cu2+ atom.