Er2Co3Cu is Hexagonal Laves-derived structured and crystallizes in the trigonal R-3m space group. Er(1) is bonded in a 16-coordinate geometry to four equivalent Er(1), nine equivalent Co(1), and three equivalent Cu(1) atoms. Co(1) is bonded to six equivalent Er(1), four equivalent Co(1), and two equivalent Cu(1) atoms to form CoEr6Co4Cu2 cuboctahedra that share corners with four equivalent Cu(1)Er6Co6 cuboctahedra, corners with fourteen equivalent Co(1)Er6Co4Cu2 cuboctahedra, edges with six equivalent Co(1)Er6Co4Cu2 cuboctahedra, faces with six equivalent Cu(1)Er6Co6 cuboctahedra, and faces with twelve equivalent Co(1)Er6Co4Cu2 cuboctahedra. Cu(1) is bonded to six equivalent Er(1) and six equivalent Co(1) atoms to form CuEr6Co6 cuboctahedra that share corners with six equivalent Cu(1)Er6Co6 cuboctahedra, corners with twelve equivalent Co(1)Er6Co4Cu2 cuboctahedra, edges with six equivalent Cu(1)Er6Co6 cuboctahedra, and faces with eighteen equivalent Co(1)Er6Co4Cu2 cuboctahedra.
Er2Co3Cu is Hexagonal Laves-derived structured and crystallizes in the trigonal R-3m space group. Er(1) is bonded in a 16-coordinate geometry to four equivalent Er(1), nine equivalent Co(1), and three equivalent Cu(1) atoms. There is one shorter (3.08 Å) and three longer (3.13 Å) Er(1)-Er(1) bond lengths. There are six shorter (2.91 Å) and three longer (3.17 Å) Er(1)-Co(1) bond lengths. All Er(1)-Cu(1) bond lengths are 2.93 Å. Co(1) is bonded to six equivalent Er(1), four equivalent Co(1), and two equivalent Cu(1) atoms to form CoEr6Co4Cu2 cuboctahedra that share corners with four equivalent Cu(1)Er6Co6 cuboctahedra, corners with fourteen equivalent Co(1)Er6Co4Cu2 cuboctahedra, edges with six equivalent Co(1)Er6Co4Cu2 cuboctahedra, faces with six equivalent Cu(1)Er6Co6 cuboctahedra, and faces with twelve equivalent Co(1)Er6Co4Cu2 cuboctahedra. All Co(1)-Co(1) bond lengths are 2.47 Å. Both Co(1)-Cu(1) bond lengths are 2.61 Å. Cu(1) is bonded to six equivalent Er(1) and six equivalent Co(1) atoms to form CuEr6Co6 cuboctahedra that share corners with six equivalent Cu(1)Er6Co6 cuboctahedra, corners with twelve equivalent Co(1)Er6Co4Cu2 cuboctahedra, edges with six equivalent Cu(1)Er6Co6 cuboctahedra, and faces with eighteen equivalent Co(1)Er6Co4Cu2 cuboctahedra.