HoGa3 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 six equivalent Ga(1) and six equivalent Ga(2) atoms to form HoGa12 cuboctahedra that share corners with six equivalent Ho(1)Ga12 cuboctahedra, corners with twelve equivalent Ga(1)Ho4Ga8 cuboctahedra, edges with six equivalent Ga(1)Ho4Ga8 cuboctahedra, faces with two equivalent Ho(1)Ga12 cuboctahedra, faces with six equivalent Ho(2)Ga12 cuboctahedra, and faces with six equivalent Ga(1)Ho4Ga8 cuboctahedra. In the second Ho site, Ho(2) is bonded to six equivalent Ga(1) and six equivalent Ga(2) atoms to form HoGa12 cuboctahedra that share corners with twelve equivalent Ho(2)Ga12 cuboctahedra, edges with twelve equivalent Ga(1)Ho4Ga8 cuboctahedra, faces with six equivalent Ho(1)Ga12 cuboctahedra, and faces with six equivalent Ga(1)Ho4Ga8 cuboctahedra. There are two inequivalent Ga sites. In the first Ga site, Ga(2) is bonded in a 10-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), two equivalent Ga(2), and four equivalent Ga(1) atoms. In the second Ga site, Ga(1) is bonded to two equivalent Ho(1), two equivalent Ho(2), four equivalent Ga(1), and four equivalent Ga(2) atoms to form distorted GaHo4Ga8 cuboctahedra that share corners with four equivalent Ho(1)Ga12 cuboctahedra, corners with fourteen equivalent Ga(1)Ho4Ga8 cuboctahedra, edges with two equivalent Ho(1)Ga12 cuboctahedra, edges with four equivalent Ho(2)Ga12 cuboctahedra, edges with four equivalent Ga(1)Ho4Ga8 cuboctahedra, faces with two equivalent Ho(1)Ga12 cuboctahedra, faces with two equivalent Ho(2)Ga12 cuboctahedra, and faces with six equivalent Ga(1)Ho4Ga8 cuboctahedra.
HoGa3 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 six equivalent Ga(1) and six equivalent Ga(2) atoms to form HoGa12 cuboctahedra that share corners with six equivalent Ho(1)Ga12 cuboctahedra, corners with twelve equivalent Ga(1)Ho4Ga8 cuboctahedra, edges with six equivalent Ga(1)Ho4Ga8 cuboctahedra, faces with two equivalent Ho(1)Ga12 cuboctahedra, faces with six equivalent Ho(2)Ga12 cuboctahedra, and faces with six equivalent Ga(1)Ho4Ga8 cuboctahedra. All Ho(1)-Ga(1) bond lengths are 3.04 Å. All Ho(1)-Ga(2) bond lengths are 3.05 Å. In the second Ho site, Ho(2) is bonded to six equivalent Ga(1) and six equivalent Ga(2) atoms to form HoGa12 cuboctahedra that share corners with twelve equivalent Ho(2)Ga12 cuboctahedra, edges with twelve equivalent Ga(1)Ho4Ga8 cuboctahedra, faces with six equivalent Ho(1)Ga12 cuboctahedra, and faces with six equivalent Ga(1)Ho4Ga8 cuboctahedra. All Ho(2)-Ga(1) bond lengths are 2.92 Å. All Ho(2)-Ga(2) bond lengths are 3.04 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(2) is bonded in a 10-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), two equivalent Ga(2), and four equivalent Ga(1) atoms. Both Ga(2)-Ga(2) bond lengths are 2.68 Å. All Ga(2)-Ga(1) bond lengths are 2.87 Å. In the second Ga site, Ga(1) is bonded to two equivalent Ho(1), two equivalent Ho(2), four equivalent Ga(1), and four equivalent Ga(2) atoms to form distorted GaHo4Ga8 cuboctahedra that share corners with four equivalent Ho(1)Ga12 cuboctahedra, corners with fourteen equivalent Ga(1)Ho4Ga8 cuboctahedra, edges with two equivalent Ho(1)Ga12 cuboctahedra, edges with four equivalent Ho(2)Ga12 cuboctahedra, edges with four equivalent Ga(1)Ho4Ga8 cuboctahedra, faces with two equivalent Ho(1)Ga12 cuboctahedra, faces with two equivalent Ho(2)Ga12 cuboctahedra, and faces with six equivalent Ga(1)Ho4Ga8 cuboctahedra. All Ga(1)-Ga(1) bond lengths are 3.04 Å.