DOE OSTI2020
Eu2CuO4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Eu3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.32 Å) and four longer (2.66 Å) Eu–O bond lengths. Cu2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.96 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Eu3+ and two equivalent Cu2+ atoms to form distorted OEu4Cu2 octahedra that share corners with two equivalent OEu4Cu2 octahedra, corners with twelve equivalent OEu4 tetrahedra, edges with two equivalent OEu4Cu2 octahedra, edges with two equivalent OEu4 tetrahedra, and faces with four equivalent OEu4Cu2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded to four equivalent Eu3+ atoms to form OEu4 tetrahedra that share corners with twelve equivalent OEu4Cu2 octahedra, corners with four equivalent OEu4 tetrahedra, edges with two equivalent OEu4Cu2 octahedra, and edges with four equivalent OEu4 tetrahedra. The corner-sharing octahedra tilt angles range from 10–69°.