ErDy crystallizes in the hexagonal P-6m2 space group. Er(1) is bonded to six equivalent Er(1) and six equivalent Dy(1) atoms to form ErDy6Er6 cuboctahedra that share corners with eighteen equivalent Er(1)Dy6Er6 cuboctahedra, edges with six equivalent Er(1)Dy6Er6 cuboctahedra, edges with twelve equivalent Dy(1)Dy6Er6 cuboctahedra, faces with eight equivalent Er(1)Dy6Er6 cuboctahedra, and faces with twelve equivalent Dy(1)Dy6Er6 cuboctahedra. Dy(1) is bonded to six equivalent Er(1) and six equivalent Dy(1) atoms to form DyDy6Er6 cuboctahedra that share corners with eighteen equivalent Dy(1)Dy6Er6 cuboctahedra, edges with six equivalent Dy(1)Dy6Er6 cuboctahedra, edges with twelve equivalent Er(1)Dy6Er6 cuboctahedra, faces with eight equivalent Dy(1)Dy6Er6 cuboctahedra, and faces with twelve equivalent Er(1)Dy6Er6 cuboctahedra.
ErDy crystallizes in the hexagonal P-6m2 space group. Er(1) is bonded to six equivalent Er(1) and six equivalent Dy(1) atoms to form ErDy6Er6 cuboctahedra that share corners with eighteen equivalent Er(1)Dy6Er6 cuboctahedra, edges with six equivalent Er(1)Dy6Er6 cuboctahedra, edges with twelve equivalent Dy(1)Dy6Er6 cuboctahedra, faces with eight equivalent Er(1)Dy6Er6 cuboctahedra, and faces with twelve equivalent Dy(1)Dy6Er6 cuboctahedra. All Er(1)-Er(1) bond lengths are 3.61 Å. All Er(1)-Dy(1) bond lengths are 3.47 Å. Dy(1) is bonded to six equivalent Er(1) and six equivalent Dy(1) atoms to form DyDy6Er6 cuboctahedra that share corners with eighteen equivalent Dy(1)Dy6Er6 cuboctahedra, edges with six equivalent Dy(1)Dy6Er6 cuboctahedra, edges with twelve equivalent Er(1)Dy6Er6 cuboctahedra, faces with eight equivalent Dy(1)Dy6Er6 cuboctahedra, and faces with twelve equivalent Er(1)Dy6Er6 cuboctahedra. All Dy(1)-Dy(1) bond lengths are 3.61 Å.