Gd2TiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(4) atoms to form distorted GdO6 octahedra that share corners with two equivalent Gd(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, edges with two equivalent Gd(2)O6 octahedra, and edges with four equivalent Gd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-63°. In the second Gd site, Gd(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form GdO6 octahedra that share corners with two equivalent Gd(1)O6 octahedra, corners with two equivalent Gd(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, edges with two equivalent Gd(1)O6 octahedra, and edges with two equivalent Gd(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-65°. 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 Gd(1)O6 octahedra, corners with four equivalent Gd(2)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-64°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(3)Gd3Ti tetrahedra, corners with four equivalent O(4)Gd3Ti tetrahedra, corners with four equivalent O(1)Gd4 tetrahedra,  an edgeedge with one O(4)Gd3Ti tetrahedra, and edges with two equivalent O(3)Gd3Ti 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 Gd(1), two equivalent Gd(2), and one Ti(1) atom to form OGd3Ti tetrahedra that share corners with two equivalent O(3)Gd3Ti tetrahedra, corners with two equivalent O(1)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Ti tetrahedra, and edges with two equivalent O(1)Gd4 tetrahedra. In the fourth O site, O(4) is bonded to three equivalent Gd(1) and one Ti(1) atom to form OGd3Ti tetrahedra that share corners with two equivalent O(4)Gd3Ti tetrahedra, corners with four equivalent O(3)Gd3Ti tetrahedra, corners with four equivalent O(1)Gd4 tetrahedra,  an edgeedge with one O(1)Gd4 tetrahedra, and edges with two equivalent O(4)Gd3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Gd(2) and one Ti(1) atom.
Gd2TiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(4) atoms to form distorted GdO6 octahedra that share corners with two equivalent Gd(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, edges with two equivalent Gd(2)O6 octahedra, and edges with four equivalent Gd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-63°. The Gd(1)-O(3) bond length is 2.33 Å. Both Gd(1)-O(1) bond lengths are 2.35 Å. There are two shorter (2.34 Å) and one longer (2.36 Å) Gd(1)-O(4) bond length. In the second Gd site, Gd(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form GdO6 octahedra that share corners with two equivalent Gd(1)O6 octahedra, corners with two equivalent Gd(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, edges with two equivalent Gd(1)O6 octahedra, and edges with two equivalent Gd(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-65°. There is one shorter (2.23 Å) and one longer (2.28 Å) Gd(2)-O(1) bond length. Both Gd(2)-O(3) bond lengths are 2.35 Å. Both Gd(2)-O(5) bond lengths are 2.40 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 Gd(1)O6 octahedra, corners with four equivalent Gd(2)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-64°. The Ti(1)-O(3) bond length is 2.07 Å. The Ti(1)-O(4) bond length is 2.02 Å. The Ti(1)-O(5) bond length is 1.84 Å. There are two shorter (1.92 Å) and one longer (2.43 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 Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(3)Gd3Ti tetrahedra, corners with four equivalent O(4)Gd3Ti tetrahedra, corners with four equivalent O(1)Gd4 tetrahedra,  an edgeedge with one O(4)Gd3Ti tetrahedra, and edges with two equivalent O(3)Gd3Ti 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 Gd(1), two equivalent Gd(2), and one Ti(1) atom to form OGd3Ti tetrahedra that share corners with two equivalent O(3)Gd3Ti tetrahedra, corners with two equivalent O(1)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Ti tetrahedra, and edges with two equivalent O(1)Gd4 tetrahedra. In the fourth O site, O(4) is bonded to three equivalent Gd(1) and one Ti(1) atom to form OGd3Ti tetrahedra that share corners with two equivalent O(4)Gd3Ti tetrahedra, corners with four equivalent O(3)Gd3Ti tetrahedra, corners with four equivalent O(1)Gd4 tetrahedra,  an edgeedge with one O(1)Gd4 tetrahedra, and edges with two equivalent O(4)Gd3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Gd(2) and one Ti(1) atom.