Hf(CoSi)2 crystallizes in the tetragonal I4/mmm space group. Hf(1) is bonded in a 16-coordinate geometry to eight equivalent Co(1) and eight equivalent Si(1) atoms. Co(1) is bonded to four equivalent Hf(1), four equivalent Co(1), and four equivalent Si(1) atoms to form a mixture of distorted corner, face, and edge-sharing CoHf4Co4Si4 cuboctahedra. Si(1) is bonded in a 9-coordinate geometry to four equivalent Hf(1), four equivalent Co(1), and one Si(1) atom.
Hf(CoSi)2 crystallizes in the tetragonal I4/mmm space group. Hf(1) is bonded in a 16-coordinate geometry to eight equivalent Co(1) and eight equivalent Si(1) atoms. All Hf(1)-Co(1) bond lengths are 3.02 Å. All Hf(1)-Si(1) bond lengths are 2.86 Å. Co(1) is bonded to four equivalent Hf(1), four equivalent Co(1), and four equivalent Si(1) atoms to form a mixture of distorted corner, face, and edge-sharing CoHf4Co4Si4 cuboctahedra. All Co(1)-Co(1) bond lengths are 2.61 Å. All Co(1)-Si(1) bond lengths are 2.22 Å. Si(1) is bonded in a 9-coordinate geometry to four equivalent Hf(1), four equivalent Co(1), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.32 Å.