Materials Data on ErCu5 by Materials Project
Cu5Er crystallizes in the cubic F-43m space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to sixteen Cu atoms. There are twelve shorter (2.90 Å) and four longer (3.03 Å) Er–Cu bond lengths. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to three equivalent Er and nine Cu atoms to form distorted CuEr3Cu9 cuboctahedra that share corners with eighteen equivalent CuEr3Cu9 cuboctahedra, corners with three equivalent CuEr4Cu12 tetrahedra, edges with six equivalent CuEr3Cu9 cuboctahedra, faces with eighteen equivalent CuEr3Cu9 cuboctahedra, and faces with seven equivalent CuEr4Cu12 tetrahedra. There are a spread of Cu–Cu bond distances ranging from 2.45–2.90 Å. In the second Cu site, Cu is bonded to four equivalent Er and twelve equivalent Cu atoms to form distorted CuEr4Cu12 tetrahedra that share corners with twelve equivalent CuEr3Cu9 cuboctahedra, faces with twenty-eight equivalent CuEr3Cu9 cuboctahedra, and faces with twelve equivalent CuEr4Cu12 tetrahedra.