Dy2Cu2O5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing DyO6 octahedra. The corner-sharing octahedral tilt angles range from 21-65°. In the second Dy site, Dy(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing DyO6 octahedra. The corner-sharing octahedral tilt angles range from 21-65°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(5) atom. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Dy(1), one Cu(1), and one Cu(2) atom to form ODy2Cu2 trigonal pyramids that share corners with three equivalent O(4)Dy3Cu tetrahedra, corners with three equivalent O(5)Dy3Cu tetrahedra, corners with two equivalent O(1)Dy2Cu2 trigonal pyramids,  an edgeedge with one O(5)Dy3Cu tetrahedra, and  an edgeedge with one O(3)Dy2Cu2 trigonal pyramid. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Dy(1), one Dy(2), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded to two equivalent Dy(2), one Cu(1), and one Cu(2) atom to form distorted ODy2Cu2 trigonal pyramids that share corners with three equivalent O(4)Dy3Cu tetrahedra, corners with three equivalent O(5)Dy3Cu tetrahedra, corners with two equivalent O(3)Dy2Cu2 trigonal pyramids,  an edgeedge with one O(4)Dy3Cu tetrahedra, and  an edgeedge with one O(1)Dy2Cu2 trigonal pyramid. In the fourth O site, O(4) is bonded to one Dy(1), two equivalent Dy(2), and one Cu(2) atom to form ODy3Cu tetrahedra that share corners with two equivalent O(4)Dy3Cu tetrahedra, corners with four equivalent O(5)Dy3Cu tetrahedra, corners with three equivalent O(1)Dy2Cu2 trigonal pyramids, corners with three equivalent O(3)Dy2Cu2 trigonal pyramids, and  an edgeedge with one O(3)Dy2Cu2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Dy(2), two equivalent Dy(1), and one Cu(1) atom to form ODy3Cu tetrahedra that share corners with two equivalent O(5)Dy3Cu tetrahedra, corners with four equivalent O(4)Dy3Cu tetrahedra, corners with three equivalent O(1)Dy2Cu2 trigonal pyramids, corners with three equivalent O(3)Dy2Cu2 trigonal pyramids, and  an edgeedge with one O(1)Dy2Cu2 trigonal pyramid.
Dy2Cu2O5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing DyO6 octahedra. The corner-sharing octahedral tilt angles range from 21-65°. The Dy(1)-O(2) bond length is 2.30 Å. The Dy(1)-O(4) bond length is 2.24 Å. There is one shorter (2.31 Å) and one longer (2.33 Å) Dy(1)-O(1) bond length. There is one shorter (2.28 Å) and one longer (2.32 Å) Dy(1)-O(5) bond length. In the second Dy site, Dy(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing DyO6 octahedra. The corner-sharing octahedral tilt angles range from 21-65°. The Dy(2)-O(2) bond length is 2.29 Å. The Dy(2)-O(5) bond length is 2.24 Å. There is one shorter (2.31 Å) and one longer (2.32 Å) Dy(2)-O(3) bond length. There is one shorter (2.30 Å) and one longer (2.31 Å) Dy(2)-O(4) bond length. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(5) atom. The Cu(1)-O(1) bond length is 1.95 Å. The Cu(1)-O(2) bond length is 1.97 Å. The Cu(1)-O(3) bond length is 2.02 Å. The Cu(1)-O(5) bond length is 2.01 Å. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Cu(2)-O(1) bond length is 2.02 Å. The Cu(2)-O(2) bond length is 1.97 Å. The Cu(2)-O(3) bond length is 1.95 Å. The Cu(2)-O(4) bond length is 2.01 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Dy(1), one Cu(1), and one Cu(2) atom to form ODy2Cu2 trigonal pyramids that share corners with three equivalent O(4)Dy3Cu tetrahedra, corners with three equivalent O(5)Dy3Cu tetrahedra, corners with two equivalent O(1)Dy2Cu2 trigonal pyramids,  an edgeedge with one O(5)Dy3Cu tetrahedra, and  an edgeedge with one O(3)Dy2Cu2 trigonal pyramid. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Dy(1), one Dy(2), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded to two equivalent Dy(2), one Cu(1), and one Cu(2) atom to form distorted ODy2Cu2 trigonal pyramids that share corners with three equivalent O(4)Dy3Cu tetrahedra, corners with three equivalent O(5)Dy3Cu tetrahedra, corners with two equivalent O(3)Dy2Cu2 trigonal pyramids,  an edgeedge with one O(4)Dy3Cu tetrahedra, and  an edgeedge with one O(1)Dy2Cu2 trigonal pyramid. In the fourth O site, O(4) is bonded to one Dy(1), two equivalent Dy(2), and one Cu(2) atom to form ODy3Cu tetrahedra that share corners with two equivalent O(4)Dy3Cu tetrahedra, corners with four equivalent O(5)Dy3Cu tetrahedra, corners with three equivalent O(1)Dy2Cu2 trigonal pyramids, corners with three equivalent O(3)Dy2Cu2 trigonal pyramids, and  an edgeedge with one O(3)Dy2Cu2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Dy(2), two equivalent Dy(1), and one Cu(1) atom to form ODy3Cu tetrahedra that share corners with two equivalent O(5)Dy3Cu tetrahedra, corners with four equivalent O(4)Dy3Cu tetrahedra, corners with three equivalent O(1)Dy2Cu2 trigonal pyramids, corners with three equivalent O(3)Dy2Cu2 trigonal pyramids, and  an edgeedge with one O(1)Dy2Cu2 trigonal pyramid.