Er5CuPb3 crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent Cu(1) and five equivalent Pb(1) atoms to form a mixture of distorted edge, corner, and face-sharing ErCu2Pb5 pentagonal bipyramids. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to six equivalent Pb(1) atoms. Cu(1) is bonded to six equivalent Er(1) atoms to form face-sharing CuEr6 octahedra. Pb(1) is bonded in a 9-coordinate geometry to four equivalent Er(2) and five equivalent Er(1) atoms.
Er5CuPb3 crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent Cu(1) and five equivalent Pb(1) atoms to form a mixture of distorted edge, corner, and face-sharing ErCu2Pb5 pentagonal bipyramids. Both Er(1)-Cu(1) bond lengths are 2.80 Å. There are a spread of Er(1)-Pb(1) bond distances ranging from 3.10-3.54 Å. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to six equivalent Pb(1) atoms. All Er(2)-Pb(1) bond lengths are 3.24 Å. Cu(1) is bonded to six equivalent Er(1) atoms to form face-sharing CuEr6 octahedra. Pb(1) is bonded in a 9-coordinate geometry to four equivalent Er(2) and five equivalent Er(1) atoms.