ErCoNi is Hexagonal Laves-derived structured and crystallizes in the orthorhombic Imma space group. Er(1) is bonded in a 12-coordinate geometry to six equivalent Co(1) and six equivalent Ni(1) atoms. Co(1) is bonded to six equivalent Er(1), two equivalent Co(1), and four equivalent Ni(1) atoms to form CoEr6Co2Ni4 cuboctahedra that share corners with eight equivalent Ni(1)Er6Co4Ni2 cuboctahedra, corners with ten equivalent Co(1)Er6Co2Ni4 cuboctahedra, edges with six equivalent Co(1)Er6Co2Ni4 cuboctahedra, faces with six equivalent Co(1)Er6Co2Ni4 cuboctahedra, and faces with twelve equivalent Ni(1)Er6Co4Ni2 cuboctahedra. Ni(1) is bonded to six equivalent Er(1), four equivalent Co(1), and two equivalent Ni(1) atoms to form NiEr6Co4Ni2 cuboctahedra that share corners with eight equivalent Co(1)Er6Co2Ni4 cuboctahedra, corners with ten equivalent Ni(1)Er6Co4Ni2 cuboctahedra, edges with six equivalent Ni(1)Er6Co4Ni2 cuboctahedra, faces with six equivalent Ni(1)Er6Co4Ni2 cuboctahedra, and faces with twelve equivalent Co(1)Er6Co2Ni4 cuboctahedra.
ErCoNi is Hexagonal Laves-derived structured and crystallizes in the orthorhombic Imma space group. Er(1) is bonded in a 12-coordinate geometry to six equivalent Co(1) and six equivalent Ni(1) atoms. There are four shorter (2.93 Å) and two longer (2.94 Å) Er(1)-Co(1) bond lengths. There are four shorter (2.92 Å) and two longer (2.96 Å) Er(1)-Ni(1) bond lengths. Co(1) is bonded to six equivalent Er(1), two equivalent Co(1), and four equivalent Ni(1) atoms to form CoEr6Co2Ni4 cuboctahedra that share corners with eight equivalent Ni(1)Er6Co4Ni2 cuboctahedra, corners with ten equivalent Co(1)Er6Co2Ni4 cuboctahedra, edges with six equivalent Co(1)Er6Co2Ni4 cuboctahedra, faces with six equivalent Co(1)Er6Co2Ni4 cuboctahedra, and faces with twelve equivalent Ni(1)Er6Co4Ni2 cuboctahedra. Both Co(1)-Co(1) bond lengths are 2.50 Å. All Co(1)-Ni(1) bond lengths are 2.51 Å. Ni(1) is bonded to six equivalent Er(1), four equivalent Co(1), and two equivalent Ni(1) atoms to form NiEr6Co4Ni2 cuboctahedra that share corners with eight equivalent Co(1)Er6Co2Ni4 cuboctahedra, corners with ten equivalent Ni(1)Er6Co4Ni2 cuboctahedra, edges with six equivalent Ni(1)Er6Co4Ni2 cuboctahedra, faces with six equivalent Ni(1)Er6Co4Ni2 cuboctahedra, and faces with twelve equivalent Co(1)Er6Co2Ni4 cuboctahedra. Both Ni(1)-Ni(1) bond lengths are 2.49 Å.