ErRh5 crystallizes in the hexagonal P6/mmm space group. Er(1) is bonded in a distorted hexagonal planar geometry to six equivalent Rh(2) and twelve equivalent Rh(1) atoms. There are two inequivalent Rh sites. In the first Rh site, Rh(1) is bonded to four equivalent Er(1), four equivalent Rh(1), and four equivalent Rh(2) atoms to form a mixture of face, corner, and edge-sharing RhEr4Rh8 cuboctahedra. In the second Rh site, Rh(2) is bonded in a 12-coordinate geometry to three equivalent Er(1), three equivalent Rh(2), and six equivalent Rh(1) atoms.
ErRh5 crystallizes in the hexagonal P6/mmm space group. Er(1) is bonded in a distorted hexagonal planar geometry to six equivalent Rh(2) and twelve equivalent Rh(1) atoms. All Er(1)-Rh(2) bond lengths are 3.02 Å. All Er(1)-Rh(1) bond lengths are 3.40 Å. There are two inequivalent Rh sites. In the first Rh site, Rh(1) is bonded to four equivalent Er(1), four equivalent Rh(1), and four equivalent Rh(2) atoms to form a mixture of face, corner, and edge-sharing RhEr4Rh8 cuboctahedra. All Rh(1)-Rh(1) bond lengths are 2.61 Å. All Rh(1)-Rh(2) bond lengths are 2.64 Å. In the second Rh site, Rh(2) is bonded in a 12-coordinate geometry to three equivalent Er(1), three equivalent Rh(2), and six equivalent Rh(1) atoms. All Rh(2)-Rh(2) bond lengths are 3.02 Å.