Co7Hf2 crystallizes in the monoclinic C2/m space group. Hf(1) is bonded in a 14-coordinate geometry to two equivalent Co(3), four equivalent Co(1), and eight equivalent Co(2) atoms. There are three inequivalent Co sites. In the first Co site, Co(3) is bonded to four equivalent Hf(1), four equivalent Co(1), and four equivalent Co(2) atoms to form a mixture of corner, face, and edge-sharing CoHf4Co8 cuboctahedra. In the second Co site, Co(1) is bonded to four equivalent Hf(1), two equivalent Co(1), two equivalent Co(3), and four equivalent Co(2) atoms to form a mixture of corner, face, and edge-sharing CoHf4Co8 cuboctahedra. In the third Co site, Co(2) is bonded in a 12-coordinate geometry to four equivalent Hf(1), one Co(3), two equivalent Co(1), and five equivalent Co(2) atoms.
Co7Hf2 crystallizes in the monoclinic C2/m space group. Hf(1) is bonded in a 14-coordinate geometry to two equivalent Co(3), four equivalent Co(1), and eight equivalent Co(2) atoms. There is one shorter (2.83 Å) and one longer (2.84 Å) Hf(1)-Co(3) bond length. There are two shorter (2.86 Å) and two longer (2.87 Å) Hf(1)-Co(1) bond lengths. There are a spread of Hf(1)-Co(2) bond distances ranging from 2.73-2.78 Å. There are three inequivalent Co sites. In the first Co site, Co(3) is bonded to four equivalent Hf(1), four equivalent Co(1), and four equivalent Co(2) atoms to form a mixture of corner, face, and edge-sharing CoHf4Co8 cuboctahedra. All Co(3)-Co(1) bond lengths are 2.37 Å. All Co(3)-Co(2) bond lengths are 2.50 Å. In the second Co site, Co(1) is bonded to four equivalent Hf(1), two equivalent Co(1), two equivalent Co(3), and four equivalent Co(2) atoms to form a mixture of corner, face, and edge-sharing CoHf4Co8 cuboctahedra. Both Co(1)-Co(1) bond lengths are 2.33 Å. There are two shorter (2.47 Å) and two longer (2.49 Å) Co(1)-Co(2) bond lengths. In the third Co site, Co(2) is bonded in a 12-coordinate geometry to four equivalent Hf(1), one Co(3), two equivalent Co(1), and five equivalent Co(2) atoms. There are a spread of Co(2)-Co(2) bond distances ranging from 2.39-2.77 Å.