Ho5Si3C crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 6-coordinate geometry to six equivalent Si(1) atoms. In the second Ho site, Ho(2) is bonded in a 2-coordinate geometry to five equivalent Si(1) and two equivalent C(1) atoms. Si(1) is bonded in a 9-coordinate geometry to four equivalent Ho(1) and five equivalent Ho(2) atoms. C(1) is bonded to six equivalent Ho(2) atoms to form face-sharing CHo6 octahedra.
Ho5Si3C crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 6-coordinate geometry to six equivalent Si(1) atoms. All Ho(1)-Si(1) bond lengths are 3.01 Å. In the second Ho site, Ho(2) is bonded in a 2-coordinate geometry to five equivalent Si(1) and two equivalent C(1) atoms. There are a spread of Ho(2)-Si(1) bond distances ranging from 2.98-3.52 Å. Both Ho(2)-C(1) bond lengths are 2.47 Å. Si(1) is bonded in a 9-coordinate geometry to four equivalent Ho(1) and five equivalent Ho(2) atoms. C(1) is bonded to six equivalent Ho(2) atoms to form face-sharing CHo6 octahedra.