Ho2RhSi3 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to twelve equivalent Si(1) atoms to form HoSi12 cuboctahedra that share edges with twelve equivalent Ho(2)Si8Rh4 cuboctahedra, faces with two equivalent Ho(1)Si12 cuboctahedra, and faces with six equivalent Ho(2)Si8Rh4 cuboctahedra. In the second Ho site, Ho(2) is bonded to four equivalent Rh(1) and eight equivalent Si(1) atoms to form HoSi8Rh4 cuboctahedra that share edges with four equivalent Ho(1)Si12 cuboctahedra, edges with eight equivalent Ho(2)Si8Rh4 cuboctahedra, faces with two equivalent Ho(1)Si12 cuboctahedra, and faces with six equivalent Ho(2)Si8Rh4 cuboctahedra. Rh(1) is bonded in a 9-coordinate geometry to six equivalent Ho(2) and three equivalent Si(1) atoms. Si(1) is bonded in a 9-coordinate geometry to two equivalent Ho(1), four equivalent Ho(2), one Rh(1), and two equivalent Si(1) atoms.
Ho2RhSi3 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to twelve equivalent Si(1) atoms to form HoSi12 cuboctahedra that share edges with twelve equivalent Ho(2)Si8Rh4 cuboctahedra, faces with two equivalent Ho(1)Si12 cuboctahedra, and faces with six equivalent Ho(2)Si8Rh4 cuboctahedra. All Ho(1)-Si(1) bond lengths are 3.06 Å. In the second Ho site, Ho(2) is bonded to four equivalent Rh(1) and eight equivalent Si(1) atoms to form HoSi8Rh4 cuboctahedra that share edges with four equivalent Ho(1)Si12 cuboctahedra, edges with eight equivalent Ho(2)Si8Rh4 cuboctahedra, faces with two equivalent Ho(1)Si12 cuboctahedra, and faces with six equivalent Ho(2)Si8Rh4 cuboctahedra. There are two shorter (3.00 Å) and two longer (3.14 Å) Ho(2)-Rh(1) bond lengths. There are four shorter (3.01 Å) and four longer (3.10 Å) Ho(2)-Si(1) bond lengths. Rh(1) is bonded in a 9-coordinate geometry to six equivalent Ho(2) and three equivalent Si(1) atoms. All Rh(1)-Si(1) bond lengths are 2.35 Å. Si(1) is bonded in a 9-coordinate geometry to two equivalent Ho(1), four equivalent Ho(2), one Rh(1), and two equivalent Si(1) atoms. Both Si(1)-Si(1) bond lengths are 2.35 Å.