Dy6Fe16O crystallizes in the cubic Im-3m space group. Dy(1) is bonded in a single-bond geometry to four equivalent Fe(1), eight equivalent Fe(2), and one O(1) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(2) is bonded to four equivalent Dy(1), two equivalent Fe(1), and six equivalent Fe(2) atoms to form distorted FeDy4Fe8 cuboctahedra that share corners with six equivalent Fe(1)Dy6Fe6 cuboctahedra, corners with eight equivalent Fe(2)Dy4Fe8 cuboctahedra, corners with two equivalent O(1)Dy6 octahedra, edges with eight equivalent Fe(2)Dy4Fe8 cuboctahedra,  an edgeedge with one O(1)Dy6 octahedra, faces with six equivalent Fe(1)Dy6Fe6 cuboctahedra, and faces with eleven equivalent Fe(2)Dy4Fe8 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. In the second Fe site, Fe(1) is bonded to six equivalent Dy(1) and six equivalent Fe(2) atoms to form FeDy6Fe6 cuboctahedra that share corners with six equivalent Fe(1)Dy6Fe6 cuboctahedra, corners with eighteen equivalent Fe(2)Dy4Fe8 cuboctahedra, faces with six equivalent Fe(1)Dy6Fe6 cuboctahedra, faces with eighteen equivalent Fe(2)Dy4Fe8 cuboctahedra, and faces with two equivalent O(1)Dy6 octahedra. O(1) is bonded to six equivalent Dy(1) atoms to form ODy6 octahedra that share corners with twenty-four equivalent Fe(2)Dy4Fe8 cuboctahedra, edges with twelve equivalent Fe(2)Dy4Fe8 cuboctahedra, and faces with eight equivalent Fe(1)Dy6Fe6 cuboctahedra.
Dy6Fe16O crystallizes in the cubic Im-3m space group. Dy(1) is bonded in a single-bond geometry to four equivalent Fe(1), eight equivalent Fe(2), and one O(1) atom. All Dy(1)-Fe(1) bond lengths are 3.34 Å. There are four shorter (3.12 Å) and four longer (3.26 Å) Dy(1)-Fe(2) bond lengths. The Dy(1)-O(1) bond length is 2.48 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(2) is bonded to four equivalent Dy(1), two equivalent Fe(1), and six equivalent Fe(2) atoms to form distorted FeDy4Fe8 cuboctahedra that share corners with six equivalent Fe(1)Dy6Fe6 cuboctahedra, corners with eight equivalent Fe(2)Dy4Fe8 cuboctahedra, corners with two equivalent O(1)Dy6 octahedra, edges with eight equivalent Fe(2)Dy4Fe8 cuboctahedra,  an edgeedge with one O(1)Dy6 octahedra, faces with six equivalent Fe(1)Dy6Fe6 cuboctahedra, and faces with eleven equivalent Fe(2)Dy4Fe8 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. Both Fe(2)-Fe(1) bond lengths are 2.63 Å. There are four shorter (2.73 Å) and two longer (3.07 Å) Fe(2)-Fe(2) bond lengths. In the second Fe site, Fe(1) is bonded to six equivalent Dy(1) and six equivalent Fe(2) atoms to form FeDy6Fe6 cuboctahedra that share corners with six equivalent Fe(1)Dy6Fe6 cuboctahedra, corners with eighteen equivalent Fe(2)Dy4Fe8 cuboctahedra, faces with six equivalent Fe(1)Dy6Fe6 cuboctahedra, faces with eighteen equivalent Fe(2)Dy4Fe8 cuboctahedra, and faces with two equivalent O(1)Dy6 octahedra. O(1) is bonded to six equivalent Dy(1) atoms to form ODy6 octahedra that share corners with twenty-four equivalent Fe(2)Dy4Fe8 cuboctahedra, edges with twelve equivalent Fe(2)Dy4Fe8 cuboctahedra, and faces with eight equivalent Fe(1)Dy6Fe6 cuboctahedra.