Er6CoBi2 crystallizes in the hexagonal P-62m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 4-coordinate geometry to two equivalent Co(1) and two equivalent Bi(1) atoms. In the second Er site, Er(2) is bonded in a 5-coordinate geometry to one Co(1) and four equivalent Bi(1) atoms. Co(1) is bonded in a 9-coordinate geometry to three equivalent Er(2) and six equivalent Er(1) atoms. Bi(1) is bonded in a 9-coordinate geometry to three equivalent Er(1) and six equivalent Er(2) atoms.
Er6CoBi2 crystallizes in the hexagonal P-62m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 4-coordinate geometry to two equivalent Co(1) and two equivalent Bi(1) atoms. Both Er(1)-Co(1) bond lengths are 2.81 Å. Both Er(1)-Bi(1) bond lengths are 3.24 Å. In the second Er site, Er(2) is bonded in a 5-coordinate geometry to one Co(1) and four equivalent Bi(1) atoms. The Er(2)-Co(1) bond length is 3.23 Å. All Er(2)-Bi(1) bond lengths are 3.27 Å. Co(1) is bonded in a 9-coordinate geometry to three equivalent Er(2) and six equivalent Er(1) atoms. Bi(1) is bonded in a 9-coordinate geometry to three equivalent Er(1) and six equivalent Er(2) atoms.