Hf2CoAl3 crystallizes in the hexagonal P6_3/mmc space group. Hf(1) is bonded in a 16-coordinate geometry to four equivalent Hf(1), three equivalent Co(1), and nine equivalent Al(1) atoms. Co(1) is bonded to six equivalent Hf(1) and six equivalent Al(1) atoms to form CoHf6Al6 cuboctahedra that share corners with twelve equivalent Al(1)Hf6Al4Co2 cuboctahedra, edges with six equivalent Co(1)Hf6Al6 cuboctahedra, faces with two equivalent Co(1)Hf6Al6 cuboctahedra, and faces with eighteen equivalent Al(1)Hf6Al4Co2 cuboctahedra. Al(1) is bonded to six equivalent Hf(1), two equivalent Co(1), and four equivalent Al(1) atoms to form distorted AlHf6Al4Co2 cuboctahedra that share corners with four equivalent Co(1)Hf6Al6 cuboctahedra, corners with fourteen equivalent Al(1)Hf6Al4Co2 cuboctahedra, edges with six equivalent Al(1)Hf6Al4Co2 cuboctahedra, faces with six equivalent Co(1)Hf6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Hf6Al4Co2 cuboctahedra.
Hf2CoAl3 crystallizes in the hexagonal P6_3/mmc space group. Hf(1) is bonded in a 16-coordinate geometry to four equivalent Hf(1), three equivalent Co(1), and nine equivalent Al(1) atoms. There is one shorter (3.12 Å) and three longer (3.18 Å) Hf(1)-Hf(1) bond lengths. All Hf(1)-Co(1) bond lengths are 3.06 Å. There are three shorter (2.97 Å) and six longer (3.04 Å) Hf(1)-Al(1) bond lengths. Co(1) is bonded to six equivalent Hf(1) and six equivalent Al(1) atoms to form CoHf6Al6 cuboctahedra that share corners with twelve equivalent Al(1)Hf6Al4Co2 cuboctahedra, edges with six equivalent Co(1)Hf6Al6 cuboctahedra, faces with two equivalent Co(1)Hf6Al6 cuboctahedra, and faces with eighteen equivalent Al(1)Hf6Al4Co2 cuboctahedra. All Co(1)-Al(1) bond lengths are 2.55 Å. Al(1) is bonded to six equivalent Hf(1), two equivalent Co(1), and four equivalent Al(1) atoms to form distorted AlHf6Al4Co2 cuboctahedra that share corners with four equivalent Co(1)Hf6Al6 cuboctahedra, corners with fourteen equivalent Al(1)Hf6Al4Co2 cuboctahedra, edges with six equivalent Al(1)Hf6Al4Co2 cuboctahedra, faces with six equivalent Co(1)Hf6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Hf6Al4Co2 cuboctahedra. There are two shorter (2.60 Å) and two longer (2.63 Å) Al(1)-Al(1) bond lengths.