Mg3Dy4Co2 crystallizes in the monoclinic P2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to one Mg(1), four equivalent Dy(1), four equivalent Dy(2), and one Co(1) atom. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to four equivalent Dy(1), four equivalent Dy(2), and two equivalent Co(1) atoms. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded in a distorted L-shaped geometry to two equivalent Mg(2), four equivalent Mg(1), and two equivalent Co(1) atoms. In the second Dy site, Dy(2) is bonded in a 4-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Co(1) atoms. Co(1) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), two equivalent Dy(1), four equivalent Dy(2), and one Co(1) atom.
Mg3Dy4Co2 crystallizes in the monoclinic P2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to one Mg(1), four equivalent Dy(1), four equivalent Dy(2), and one Co(1) atom. The Mg(1)-Mg(1) bond length is 3.12 Å. There are two shorter (3.29 Å) and two longer (3.42 Å) Mg(1)-Dy(1) bond lengths. There are two shorter (3.44 Å) and two longer (3.52 Å) Mg(1)-Dy(2) bond lengths. The Mg(1)-Co(1) bond length is 3.20 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to four equivalent Dy(1), four equivalent Dy(2), and two equivalent Co(1) atoms. All Mg(2)-Dy(1) bond lengths are 3.19 Å. All Mg(2)-Dy(2) bond lengths are 3.38 Å. Both Mg(2)-Co(1) bond lengths are 3.06 Å. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded in a distorted L-shaped geometry to two equivalent Mg(2), four equivalent Mg(1), and two equivalent Co(1) atoms. Both Dy(1)-Co(1) bond lengths are 2.69 Å. In the second Dy site, Dy(2) is bonded in a 4-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Co(1) atoms. There are two shorter (2.84 Å) and two longer (2.88 Å) Dy(2)-Co(1) bond lengths. Co(1) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), two equivalent Dy(1), four equivalent Dy(2), and one Co(1) atom. The Co(1)-Co(1) bond length is 2.32 Å.