Materials Data on Ba2ErCuNi2O7 by Materials Project
Ba2ErNi2CuO7 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. Ba2+ is bonded in a distorted q6 geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.78–3.00 Å. Er3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.40 Å) and four longer (2.42 Å) Er–O bond lengths. Ni3+ is bonded to five O2- atoms to form corner-sharing NiO5 square pyramids. There are a spread of Ni–O bond distances ranging from 1.99–2.08 Å. Cu1+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.88 Å) and two longer (1.98 Å) Cu–O bond length. 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 Er3+, and two equivalent Ni3+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, two equivalent Er3+, and two equivalent Ni3+ atoms. In the third O2- site, O2- is bonded to four equivalent Ba2+, one Ni3+, and one Cu1+ atom to form distorted OBa4CuNi octahedra that share corners with nine OBa4CuNi octahedra, edges with four equivalent OBa4CuNi octahedra, and faces with two equivalent OBa4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–65°. In the fourth O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Cu1+ atoms to form distorted OBa4Cu2 octahedra that share corners with ten OBa4CuNi octahedra, edges with two equivalent OBa4Cu2 octahedra, and faces with four equivalent OBa4CuNi octahedra. The corner-sharing octahedra tilt angles range from 0–65°.