Dy2TiO5 crystallizes in the orthorhombic Cmcm space group. Dy(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(2) atoms to form distorted DyO6 pentagonal pyramids that share  a cornercorner with one Ti(1)O6 octahedra, corners with three equivalent Dy(1)O6 pentagonal pyramids, edges with three equivalent Ti(1)O6 octahedra, and edges with three equivalent Dy(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 31°. Ti(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Dy(1)O6 pentagonal pyramids, and edges with six equivalent Dy(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 32°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Dy(1) and one Ti(1) atom. In the second O site, O(2) is bonded to three equivalent Dy(1) and one Ti(1) atom to form ODy3Ti trigonal pyramids that share  a cornercorner with one O(3)Dy2Ti2 tetrahedra, corners with three equivalent O(2)Dy3Ti trigonal pyramids, edges with two equivalent O(3)Dy2Ti2 tetrahedra, and edges with two equivalent O(2)Dy3Ti trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Dy(1) and two equivalent Ti(1) atoms to form distorted ODy2Ti2 tetrahedra that share corners with two equivalent O(3)Dy2Ti2 tetrahedra, corners with two equivalent O(2)Dy3Ti trigonal pyramids, and edges with four equivalent O(2)Dy3Ti trigonal pyramids.
Dy2TiO5 crystallizes in the orthorhombic Cmcm space group. Dy(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(2) atoms to form distorted DyO6 pentagonal pyramids that share  a cornercorner with one Ti(1)O6 octahedra, corners with three equivalent Dy(1)O6 pentagonal pyramids, edges with three equivalent Ti(1)O6 octahedra, and edges with three equivalent Dy(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 31°. The Dy(1)-O(3) bond length is 2.40 Å. There is one shorter (2.23 Å) and one longer (2.28 Å) Dy(1)-O(1) bond length. There are two shorter (2.19 Å) and one longer (2.35 Å) Dy(1)-O(2) bond length. Ti(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Dy(1)O6 pentagonal pyramids, and edges with six equivalent Dy(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 32°. Both Ti(1)-O(1) bond lengths are 1.87 Å. Both Ti(1)-O(2) bond lengths are 2.12 Å. Both Ti(1)-O(3) bond lengths are 2.13 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Dy(1) and one Ti(1) atom. In the second O site, O(2) is bonded to three equivalent Dy(1) and one Ti(1) atom to form ODy3Ti trigonal pyramids that share  a cornercorner with one O(3)Dy2Ti2 tetrahedra, corners with three equivalent O(2)Dy3Ti trigonal pyramids, edges with two equivalent O(3)Dy2Ti2 tetrahedra, and edges with two equivalent O(2)Dy3Ti trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Dy(1) and two equivalent Ti(1) atoms to form distorted ODy2Ti2 tetrahedra that share corners with two equivalent O(3)Dy2Ti2 tetrahedra, corners with two equivalent O(2)Dy3Ti trigonal pyramids, and edges with four equivalent O(2)Dy3Ti trigonal pyramids.