Ho2CoSi2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 10-coordinate geometry to four equivalent Co(1), two equivalent Si(2), and five equivalent Si(1) atoms. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to two equivalent Co(1), one Si(1), and five equivalent Si(2) atoms. Co(1) is bonded in a 10-coordinate geometry to two equivalent Ho(2), four equivalent Ho(1), one Si(2), and three equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to one Ho(2), five equivalent Ho(1), three equivalent Co(1), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ho(1), five equivalent Ho(2), one Co(1), and one Si(2) atom.
Ho2CoSi2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 10-coordinate geometry to four equivalent Co(1), two equivalent Si(2), and five equivalent Si(1) atoms. There are a spread of Ho(1)-Co(1) bond distances ranging from 2.91-3.06 Å. Both Ho(1)-Si(2) bond lengths are 2.86 Å. There are a spread of Ho(1)-Si(1) bond distances ranging from 2.94-3.19 Å. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to two equivalent Co(1), one Si(1), and five equivalent Si(2) atoms. Both Ho(2)-Co(1) bond lengths are 3.25 Å. The Ho(2)-Si(1) bond length is 2.88 Å. There are a spread of Ho(2)-Si(2) bond distances ranging from 2.93-3.09 Å. Co(1) is bonded in a 10-coordinate geometry to two equivalent Ho(2), four equivalent Ho(1), one Si(2), and three equivalent Si(1) atoms. The Co(1)-Si(2) bond length is 2.46 Å. There are two shorter (2.33 Å) and one longer (2.37 Å) Co(1)-Si(1) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to one Ho(2), five equivalent Ho(1), three equivalent Co(1), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.76 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ho(1), five equivalent Ho(2), one Co(1), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.52 Å.