Dy2TiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded in a 6-coordinate geometry to one O(3), two equivalent O(1), and three equivalent O(4) atoms. In the second Dy site, Dy(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form DyO6 octahedra that share corners with two equivalent Dy(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, and edges with two equivalent Dy(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-65°. Ti(1) is bonded to one O(3), one O(4), one O(5), and three equivalent O(2) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Dy(2)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-64°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Dy(1) and two equivalent Dy(2) atoms to form ODy4 tetrahedra that share corners with two equivalent O(3)Dy3Ti tetrahedra, corners with four equivalent O(4)Dy3Ti tetrahedra, corners with four equivalent O(1)Dy4 tetrahedra,  an edgeedge with one O(4)Dy3Ti tetrahedra, and edges with two equivalent O(3)Dy3Ti tetrahedra. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ti(1) atoms. In the third O site, O(3) is bonded to one Dy(1), two equivalent Dy(2), and one Ti(1) atom to form ODy3Ti tetrahedra that share corners with two equivalent O(3)Dy3Ti tetrahedra, corners with two equivalent O(1)Dy4 tetrahedra, corners with four equivalent O(4)Dy3Ti tetrahedra, and edges with two equivalent O(1)Dy4 tetrahedra. In the fourth O site, O(4) is bonded to three equivalent Dy(1) and one Ti(1) atom to form ODy3Ti tetrahedra that share corners with two equivalent O(4)Dy3Ti tetrahedra, corners with four equivalent O(3)Dy3Ti tetrahedra, corners with four equivalent O(1)Dy4 tetrahedra,  an edgeedge with one O(1)Dy4 tetrahedra, and edges with two equivalent O(4)Dy3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Dy(2) and one Ti(1) atom.
Dy2TiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded in a 6-coordinate geometry to one O(3), two equivalent O(1), and three equivalent O(4) atoms. The Dy(1)-O(3) bond length is 2.34 Å. Both Dy(1)-O(1) bond lengths are 2.31 Å. All Dy(1)-O(4) bond lengths are 2.31 Å. In the second Dy site, Dy(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form DyO6 octahedra that share corners with two equivalent Dy(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, and edges with two equivalent Dy(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-65°. There is one shorter (2.21 Å) and one longer (2.23 Å) Dy(2)-O(1) bond length. Both Dy(2)-O(3) bond lengths are 2.30 Å. Both Dy(2)-O(5) bond lengths are 2.36 Å. Ti(1) is bonded to one O(3), one O(4), one O(5), and three equivalent O(2) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Dy(2)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-64°. The Ti(1)-O(3) bond length is 2.05 Å. The Ti(1)-O(4) bond length is 2.01 Å. The Ti(1)-O(5) bond length is 1.86 Å. There are two shorter (1.90 Å) and one longer (2.42 Å) Ti(1)-O(2) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Dy(1) and two equivalent Dy(2) atoms to form ODy4 tetrahedra that share corners with two equivalent O(3)Dy3Ti tetrahedra, corners with four equivalent O(4)Dy3Ti tetrahedra, corners with four equivalent O(1)Dy4 tetrahedra,  an edgeedge with one O(4)Dy3Ti tetrahedra, and edges with two equivalent O(3)Dy3Ti tetrahedra. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ti(1) atoms. In the third O site, O(3) is bonded to one Dy(1), two equivalent Dy(2), and one Ti(1) atom to form ODy3Ti tetrahedra that share corners with two equivalent O(3)Dy3Ti tetrahedra, corners with two equivalent O(1)Dy4 tetrahedra, corners with four equivalent O(4)Dy3Ti tetrahedra, and edges with two equivalent O(1)Dy4 tetrahedra. In the fourth O site, O(4) is bonded to three equivalent Dy(1) and one Ti(1) atom to form ODy3Ti tetrahedra that share corners with two equivalent O(4)Dy3Ti tetrahedra, corners with four equivalent O(3)Dy3Ti tetrahedra, corners with four equivalent O(1)Dy4 tetrahedra,  an edgeedge with one O(1)Dy4 tetrahedra, and edges with two equivalent O(4)Dy3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Dy(2) and one Ti(1) atom.