DOE OSTI2020
Dy2BaCoO5 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 2.73–3.32 Å. There are two inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded to seven O2- atoms to form distorted DyO7 pentagonal bipyramids that share corners with five equivalent CoO5 trigonal bipyramids, edges with five DyO7 pentagonal bipyramids, an edgeedge with one CoO5 trigonal bipyramid, and a faceface with one DyO7 pentagonal bipyramid. There are a spread of Dy–O bond distances ranging from 2.32–2.38 Å. In the second Dy3+ site, Dy3+ is bonded to seven O2- atoms to form distorted DyO7 pentagonal bipyramids that share corners with four equivalent DyO7 pentagonal bipyramids, edges with three equivalent DyO7 pentagonal bipyramids, edges with two equivalent CoO5 trigonal bipyramids, a faceface with one DyO7 pentagonal bipyramid, and a faceface with one CoO5 trigonal bipyramid. There are a spread of Dy–O bond distances ranging from 2.32–2.39 Å. Co2+ is bonded to five O2- atoms to form CoO5 trigonal bipyramids that share corners with five equivalent DyO7 pentagonal bipyramids, edges with three DyO7 pentagonal bipyramids, and a faceface with one DyO7 pentagonal bipyramid. There are a spread of Co–O bond distances ranging from 2.01–2.12 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ba2+, two Dy3+, and one Co2+ atom to form a mixture of distorted corner and edge-sharing OBa3Dy2Co octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, three Dy3+, and one Co2+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, three Dy3+, and one Co2+ atom.