Dy8CoGa3 crystallizes in the hexagonal P6_3mc space group. There are four inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one Co(1) and three equivalent Ga(1) atoms to form distorted DyGa3Co trigonal pyramids that share  a cornercorner with one Dy(4)Ga6 octahedra, corners with two equivalent Dy(2)Ga3Co tetrahedra, corners with eight equivalent Dy(1)Ga3Co trigonal pyramids,  an edgeedge with one Dy(4)Ga6 octahedra,  an edgeedge with one Dy(2)Ga3Co tetrahedra, and  a faceface with one Dy(4)Ga6 octahedra. The corner-sharing octahedral tilt angles are 54°. In the second Dy site, Dy(2) is bonded to one Co(1) and three equivalent Ga(1) atoms to form distorted DyGa3Co tetrahedra that share corners with six equivalent Dy(4)Ga6 octahedra, corners with six equivalent Dy(1)Ga3Co trigonal pyramids, and edges with three equivalent Dy(1)Ga3Co trigonal pyramids. The corner-sharing octahedral tilt angles range from 16-46°. In the third Dy site, Dy(3) is bonded in a 3-coordinate geometry to one Co(1) and two equivalent Ga(1) atoms. In the fourth Dy site, Dy(4) is bonded to six equivalent Ga(1) atoms to form distorted DyGa6 octahedra that share corners with six equivalent Dy(2)Ga3Co tetrahedra, corners with three equivalent Dy(1)Ga3Co trigonal pyramids, edges with three equivalent Dy(1)Ga3Co trigonal pyramids, faces with two equivalent Dy(4)Ga6 octahedra, and faces with three equivalent Dy(1)Ga3Co trigonal pyramids. Co(1) is bonded in a 7-coordinate geometry to one Dy(2), three equivalent Dy(1), and three equivalent Dy(3) atoms. Ga(1) is bonded in a 8-coordinate geometry to one Dy(2), two equivalent Dy(3), two equivalent Dy(4), and three equivalent Dy(1) atoms.
Dy8CoGa3 crystallizes in the hexagonal P6_3mc space group. There are four inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one Co(1) and three equivalent Ga(1) atoms to form distorted DyGa3Co trigonal pyramids that share  a cornercorner with one Dy(4)Ga6 octahedra, corners with two equivalent Dy(2)Ga3Co tetrahedra, corners with eight equivalent Dy(1)Ga3Co trigonal pyramids,  an edgeedge with one Dy(4)Ga6 octahedra,  an edgeedge with one Dy(2)Ga3Co tetrahedra, and  a faceface with one Dy(4)Ga6 octahedra. The corner-sharing octahedral tilt angles are 54°. The Dy(1)-Co(1) bond length is 2.83 Å. There are two shorter (2.94 Å) and one longer (3.12 Å) Dy(1)-Ga(1) bond length. In the second Dy site, Dy(2) is bonded to one Co(1) and three equivalent Ga(1) atoms to form distorted DyGa3Co tetrahedra that share corners with six equivalent Dy(4)Ga6 octahedra, corners with six equivalent Dy(1)Ga3Co trigonal pyramids, and edges with three equivalent Dy(1)Ga3Co trigonal pyramids. The corner-sharing octahedral tilt angles range from 16-46°. The Dy(2)-Co(1) bond length is 2.65 Å. All Dy(2)-Ga(1) bond lengths are 3.09 Å. In the third Dy site, Dy(3) is bonded in a 3-coordinate geometry to one Co(1) and two equivalent Ga(1) atoms. The Dy(3)-Co(1) bond length is 2.79 Å. Both Dy(3)-Ga(1) bond lengths are 3.17 Å. In the fourth Dy site, Dy(4) is bonded to six equivalent Ga(1) atoms to form distorted DyGa6 octahedra that share corners with six equivalent Dy(2)Ga3Co tetrahedra, corners with three equivalent Dy(1)Ga3Co trigonal pyramids, edges with three equivalent Dy(1)Ga3Co trigonal pyramids, faces with two equivalent Dy(4)Ga6 octahedra, and faces with three equivalent Dy(1)Ga3Co trigonal pyramids. There are three shorter (3.25 Å) and three longer (3.40 Å) Dy(4)-Ga(1) bond lengths. Co(1) is bonded in a 7-coordinate geometry to one Dy(2), three equivalent Dy(1), and three equivalent Dy(3) atoms. Ga(1) is bonded in a 8-coordinate geometry to one Dy(2), two equivalent Dy(3), two equivalent Dy(4), and three equivalent Dy(1) atoms.