Ho2Cu2O5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing HoO6 octahedra. The corner-sharing octahedral tilt angles range from 22-64°. In the second Ho site, Ho(2) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing HoO6 octahedra. The corner-sharing octahedral tilt angles range from 22-64°. 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(2), one O(3), one O(4), 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(5) is bonded to one Ho(2), two equivalent Ho(1), and one Cu(1) atom to form OHo3Cu tetrahedra that share corners with two equivalent O(5)Ho3Cu tetrahedra, corners with four equivalent O(1)Ho3Cu tetrahedra, corners with three equivalent O(2)Ho2Cu2 trigonal pyramids, corners with three equivalent O(4)Ho2Cu2 trigonal pyramids, and  an edgeedge with one O(2)Ho2Cu2 trigonal pyramid. In the second O site, O(1) is bonded to one Ho(1), two equivalent Ho(2), and one Cu(2) atom to form OHo3Cu tetrahedra that share corners with two equivalent O(1)Ho3Cu tetrahedra, corners with four equivalent O(5)Ho3Cu tetrahedra, corners with three equivalent O(2)Ho2Cu2 trigonal pyramids, corners with three equivalent O(4)Ho2Cu2 trigonal pyramids, and  an edgeedge with one O(4)Ho2Cu2 trigonal pyramid. In the third O site, O(2) is bonded to two equivalent Ho(1), one Cu(1), and one Cu(2) atom to form distorted OHo2Cu2 trigonal pyramids that share corners with three equivalent O(1)Ho3Cu tetrahedra, corners with three equivalent O(5)Ho3Cu tetrahedra, corners with two equivalent O(2)Ho2Cu2 trigonal pyramids,  an edgeedge with one O(5)Ho3Cu tetrahedra, and  an edgeedge with one O(4)Ho2Cu2 trigonal pyramid. In the fourth O site, O(3) is bonded in a distorted see-saw-like geometry to one Ho(1), one Ho(2), one Cu(1), and one Cu(2) atom. In the fifth O site, O(4) is bonded to two equivalent Ho(2), one Cu(1), and one Cu(2) atom to form distorted OHo2Cu2 trigonal pyramids that share corners with three equivalent O(1)Ho3Cu tetrahedra, corners with three equivalent O(5)Ho3Cu tetrahedra, corners with two equivalent O(4)Ho2Cu2 trigonal pyramids,  an edgeedge with one O(1)Ho3Cu tetrahedra, and  an edgeedge with one O(2)Ho2Cu2 trigonal pyramid.
Ho2Cu2O5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing HoO6 octahedra. The corner-sharing octahedral tilt angles range from 22-64°. The Ho(1)-O(1) bond length is 2.23 Å. The Ho(1)-O(3) bond length is 2.28 Å. There is one shorter (2.30 Å) and one longer (2.31 Å) Ho(1)-O(2) bond length. There is one shorter (2.28 Å) and one longer (2.29 Å) Ho(1)-O(5) bond length. In the second Ho site, Ho(2) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing HoO6 octahedra. The corner-sharing octahedral tilt angles range from 22-64°. The Ho(2)-O(3) bond length is 2.28 Å. The Ho(2)-O(5) bond length is 2.22 Å. There is one shorter (2.27 Å) and one longer (2.30 Å) Ho(2)-O(1) bond length. There is one shorter (2.29 Å) and one longer (2.31 Å) Ho(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(2), one O(3), one O(4), and one O(5) atom. The Cu(1)-O(2) bond length is 1.94 Å. The Cu(1)-O(3) bond length is 1.96 Å. The Cu(1)-O(4) 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 2.01 Å. The Cu(2)-O(2) bond length is 2.01 Å. The Cu(2)-O(3) bond length is 1.97 Å. The Cu(2)-O(4) bond length is 1.95 Å. There are five inequivalent O sites. In the first O site, O(5) is bonded to one Ho(2), two equivalent Ho(1), and one Cu(1) atom to form OHo3Cu tetrahedra that share corners with two equivalent O(5)Ho3Cu tetrahedra, corners with four equivalent O(1)Ho3Cu tetrahedra, corners with three equivalent O(2)Ho2Cu2 trigonal pyramids, corners with three equivalent O(4)Ho2Cu2 trigonal pyramids, and  an edgeedge with one O(2)Ho2Cu2 trigonal pyramid. In the second O site, O(1) is bonded to one Ho(1), two equivalent Ho(2), and one Cu(2) atom to form OHo3Cu tetrahedra that share corners with two equivalent O(1)Ho3Cu tetrahedra, corners with four equivalent O(5)Ho3Cu tetrahedra, corners with three equivalent O(2)Ho2Cu2 trigonal pyramids, corners with three equivalent O(4)Ho2Cu2 trigonal pyramids, and  an edgeedge with one O(4)Ho2Cu2 trigonal pyramid. In the third O site, O(2) is bonded to two equivalent Ho(1), one Cu(1), and one Cu(2) atom to form distorted OHo2Cu2 trigonal pyramids that share corners with three equivalent O(1)Ho3Cu tetrahedra, corners with three equivalent O(5)Ho3Cu tetrahedra, corners with two equivalent O(2)Ho2Cu2 trigonal pyramids,  an edgeedge with one O(5)Ho3Cu tetrahedra, and  an edgeedge with one O(4)Ho2Cu2 trigonal pyramid. In the fourth O site, O(3) is bonded in a distorted see-saw-like geometry to one Ho(1), one Ho(2), one Cu(1), and one Cu(2) atom. In the fifth O site, O(4) is bonded to two equivalent Ho(2), one Cu(1), and one Cu(2) atom to form distorted OHo2Cu2 trigonal pyramids that share corners with three equivalent O(1)Ho3Cu tetrahedra, corners with three equivalent O(5)Ho3Cu tetrahedra, corners with two equivalent O(4)Ho2Cu2 trigonal pyramids,  an edgeedge with one O(1)Ho3Cu tetrahedra, and  an edgeedge with one O(2)Ho2Cu2 trigonal pyramid.