La5Ti5O17 crystallizes in the monoclinic Pc space group. There are five inequivalent La sites. In the first La site, La(1) is bonded in a 10-coordinate geometry to one O(1), one O(7), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. In the second La site, La(2) is bonded to one O(10), one O(4), two equivalent O(5), two equivalent O(6), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms to form distorted LaO12 cuboctahedra that share corners with two equivalent La(2)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(2)O6 octahedra, faces with two equivalent Ti(4)O6 octahedra, and faces with four equivalent Ti(3)O6 octahedra. In the third La site, La(3) is bonded in a 12-coordinate geometry to one O(15), one O(7), two equivalent O(10), two equivalent O(16), two equivalent O(17), two equivalent O(8), and two equivalent O(9) atoms. In the fourth La site, La(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(15), two equivalent O(13), and two equivalent O(14) atoms. In the fifth La site, La(5) is bonded in a 7-coordinate geometry to one O(1), one O(13), one O(14), two equivalent O(11), and two equivalent O(12) atoms. There are five inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(11), one O(12), one O(2), one O(3), and two equivalent O(1) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 14-36°. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 14-36°. In the third Ti site, Ti(3) is bonded to one O(5), one O(6), one O(8), one O(9), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and faces with four equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-24°. In the fourth Ti site, Ti(4) is bonded to one O(16), one O(17), one O(8), one O(9), and two equivalent O(10) atoms to form TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Ti(5)O6 octahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 15-37°. In the fifth Ti site, Ti(5) is bonded to one O(13), one O(14), one O(16), one O(17), and two equivalent O(15) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 15-37°. There are seventeen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one La(1), one La(5), and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent La(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded to two equivalent La(1), one Ti(1), and one Ti(2) atom to form distorted OLa2Ti2 tetrahedra that share corners with two equivalent O(4)La3Ti2 square pyramids,  a cornercorner with one O(11)La3Ti tetrahedra, corners with two equivalent O(3)La2Ti2 tetrahedra, and edges with two equivalent O(4)La3Ti2 square pyramids. In the fourth O site, O(4) is bonded to one La(2), two equivalent La(1), and two equivalent Ti(2) atoms to form distorted OLa3Ti2 square pyramids that share  a cornercorner with one O(10)La3Ti2 square pyramid, corners with four equivalent O(4)La3Ti2 square pyramids, corners with two equivalent O(3)La2Ti2 tetrahedra, and edges with two equivalent O(3)La2Ti2 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent La(1), two equivalent La(2), one Ti(2), and one Ti(3) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent La(2), one Ti(2), and one Ti(3) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one La(1), one La(3), two equivalent La(2), and two equivalent Ti(3) atoms. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent La(2), two equivalent La(3), one Ti(3), and one Ti(4) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to two equivalent La(2), two equivalent La(3), one Ti(3), and one Ti(4) atom. In the tenth O site, O(10) is bonded to one La(2), two equivalent La(3), and two equivalent Ti(4) atoms to form distorted OLa3Ti2 square pyramids that share  a cornercorner with one O(4)La3Ti2 square pyramid, corners with four equivalent O(10)La3Ti2 square pyramids, corners with two equivalent O(17)La2Ti2 tetrahedra, and edges with two equivalent O(17)La2Ti2 tetrahedra. In the eleventh O site, O(11) is bonded to one La(4), two equivalent La(5), and one Ti(1) atom to form OLa3Ti tetrahedra that share  a cornercorner with one O(3)La2Ti2 tetrahedra, corners with two equivalent O(11)La3Ti tetrahedra, and corners with four equivalent O(14)La3Ti tetrahedra. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one La(4), two equivalent La(5), and one Ti(1) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one La(5), two equivalent La(4), and one Ti(5) atom. In the fourteenth O site, O(14) is bonded to one La(5), two equivalent La(4), and one Ti(5) atom to form distorted OLa3Ti tetrahedra that share  a cornercorner with one O(17)La2Ti2 tetrahedra, corners with two equivalent O(14)La3Ti tetrahedra, and corners with four equivalent O(11)La3Ti tetrahedra. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one La(3), one La(4), and two equivalent Ti(5) atoms. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to two equivalent La(3), one Ti(4), and one Ti(5) atom. In the seventeenth O site, O(17) is bonded to two equivalent La(3), one Ti(4), and one Ti(5) atom to form distorted OLa2Ti2 tetrahedra that share corners with two equivalent O(10)La3Ti2 square pyramids,  a cornercorner with one O(14)La3Ti tetrahedra, corners with two equivalent O(17)La2Ti2 tetrahedra, and edges with two equivalent O(10)La3Ti2 square pyramids.
La5Ti5O17 crystallizes in the monoclinic Pc space group. There are five inequivalent La sites. In the first La site, La(1) is bonded in a 10-coordinate geometry to one O(1), one O(7), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. The La(1)-O(1) bond length is 2.47 Å. The La(1)-O(7) bond length is 2.89 Å. Both La(1)-O(2) bond lengths are 2.83 Å. Both La(1)-O(3) bond lengths are 2.44 Å. There is one shorter (2.73 Å) and one longer (2.80 Å) La(1)-O(4) bond length. Both La(1)-O(5) bond lengths are 2.59 Å. In the second La site, La(2) is bonded to one O(10), one O(4), two equivalent O(5), two equivalent O(6), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms to form distorted LaO12 cuboctahedra that share corners with two equivalent La(2)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(2)O6 octahedra, faces with two equivalent Ti(4)O6 octahedra, and faces with four equivalent Ti(3)O6 octahedra. The La(2)-O(10) bond length is 2.61 Å. The La(2)-O(4) bond length is 2.61 Å. Both La(2)-O(5) bond lengths are 3.01 Å. Both La(2)-O(6) bond lengths are 2.51 Å. Both La(2)-O(7) bond lengths are 2.75 Å. There is one shorter (2.51 Å) and one longer (2.52 Å) La(2)-O(8) bond length. Both La(2)-O(9) bond lengths are 3.01 Å. In the third La site, La(3) is bonded in a 12-coordinate geometry to one O(15), one O(7), two equivalent O(10), two equivalent O(16), two equivalent O(17), two equivalent O(8), and two equivalent O(9) atoms. The La(3)-O(15) bond length is 2.47 Å. The La(3)-O(7) bond length is 2.89 Å. There is one shorter (2.74 Å) and one longer (2.79 Å) La(3)-O(10) bond length. There is one shorter (2.84 Å) and one longer (2.85 Å) La(3)-O(16) bond length. Both La(3)-O(17) bond lengths are 2.44 Å. There is one shorter (3.16 Å) and one longer (3.17 Å) La(3)-O(8) bond length. Both La(3)-O(9) bond lengths are 2.59 Å. In the fourth La site, La(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(15), two equivalent O(13), and two equivalent O(14) atoms. The La(4)-O(11) bond length is 2.41 Å. The La(4)-O(12) bond length is 2.68 Å. The La(4)-O(15) bond length is 2.68 Å. Both La(4)-O(13) bond lengths are 2.48 Å. There is one shorter (2.40 Å) and one longer (2.41 Å) La(4)-O(14) bond length. In the fifth La site, La(5) is bonded in a 7-coordinate geometry to one O(1), one O(13), one O(14), two equivalent O(11), and two equivalent O(12) atoms. The La(5)-O(1) bond length is 2.72 Å. The La(5)-O(13) bond length is 2.65 Å. The La(5)-O(14) bond length is 2.42 Å. Both La(5)-O(11) bond lengths are 2.41 Å. Both La(5)-O(12) bond lengths are 2.47 Å. There are five inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(11), one O(12), one O(2), one O(3), and two equivalent O(1) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 14-36°. The Ti(1)-O(11) bond length is 1.90 Å. The Ti(1)-O(12) bond length is 1.82 Å. The Ti(1)-O(2) bond length is 2.17 Å. The Ti(1)-O(3) bond length is 1.99 Å. Both Ti(1)-O(1) bond lengths are 1.99 Å. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 14-36°. The Ti(2)-O(2) bond length is 1.83 Å. The Ti(2)-O(3) bond length is 1.93 Å. The Ti(2)-O(5) bond length is 2.03 Å. The Ti(2)-O(6) bond length is 2.12 Å. Both Ti(2)-O(4) bond lengths are 1.99 Å. In the third Ti site, Ti(3) is bonded to one O(5), one O(6), one O(8), one O(9), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and faces with four equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-24°. The Ti(3)-O(5) bond length is 1.97 Å. The Ti(3)-O(6) bond length is 1.95 Å. The Ti(3)-O(8) bond length is 1.95 Å. The Ti(3)-O(9) bond length is 1.97 Å. There is one shorter (1.97 Å) and one longer (1.98 Å) Ti(3)-O(7) bond length. In the fourth Ti site, Ti(4) is bonded to one O(16), one O(17), one O(8), one O(9), and two equivalent O(10) atoms to form TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Ti(5)O6 octahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 15-37°. The Ti(4)-O(16) bond length is 1.83 Å. The Ti(4)-O(17) bond length is 1.93 Å. The Ti(4)-O(8) bond length is 2.12 Å. The Ti(4)-O(9) bond length is 2.02 Å. Both Ti(4)-O(10) bond lengths are 1.99 Å. In the fifth Ti site, Ti(5) is bonded to one O(13), one O(14), one O(16), one O(17), and two equivalent O(15) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 15-37°. The Ti(5)-O(13) bond length is 1.82 Å. The Ti(5)-O(14) bond length is 1.90 Å. The Ti(5)-O(16) bond length is 2.18 Å. The Ti(5)-O(17) bond length is 1.98 Å. Both Ti(5)-O(15) bond lengths are 1.99 Å. There are seventeen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one La(1), one La(5), and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent La(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded to two equivalent La(1), one Ti(1), and one Ti(2) atom to form distorted OLa2Ti2 tetrahedra that share corners with two equivalent O(4)La3Ti2 square pyramids,  a cornercorner with one O(11)La3Ti tetrahedra, corners with two equivalent O(3)La2Ti2 tetrahedra, and edges with two equivalent O(4)La3Ti2 square pyramids. In the fourth O site, O(4) is bonded to one La(2), two equivalent La(1), and two equivalent Ti(2) atoms to form distorted OLa3Ti2 square pyramids that share  a cornercorner with one O(10)La3Ti2 square pyramid, corners with four equivalent O(4)La3Ti2 square pyramids, corners with two equivalent O(3)La2Ti2 tetrahedra, and edges with two equivalent O(3)La2Ti2 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent La(1), two equivalent La(2), one Ti(2), and one Ti(3) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent La(2), one Ti(2), and one Ti(3) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one La(1), one La(3), two equivalent La(2), and two equivalent Ti(3) atoms. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent La(2), two equivalent La(3), one Ti(3), and one Ti(4) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to two equivalent La(2), two equivalent La(3), one Ti(3), and one Ti(4) atom. In the tenth O site, O(10) is bonded to one La(2), two equivalent La(3), and two equivalent Ti(4) atoms to form distorted OLa3Ti2 square pyramids that share  a cornercorner with one O(4)La3Ti2 square pyramid, corners with four equivalent O(10)La3Ti2 square pyramids, corners with two equivalent O(17)La2Ti2 tetrahedra, and edges with two equivalent O(17)La2Ti2 tetrahedra. In the eleventh O site, O(11) is bonded to one La(4), two equivalent La(5), and one Ti(1) atom to form OLa3Ti tetrahedra that share  a cornercorner with one O(3)La2Ti2 tetrahedra, corners with two equivalent O(11)La3Ti tetrahedra, and corners with four equivalent O(14)La3Ti tetrahedra. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one La(4), two equivalent La(5), and one Ti(1) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one La(5), two equivalent La(4), and one Ti(5) atom. In the fourteenth O site, O(14) is bonded to one La(5), two equivalent La(4), and one Ti(5) atom to form distorted OLa3Ti tetrahedra that share  a cornercorner with one O(17)La2Ti2 tetrahedra, corners with two equivalent O(14)La3Ti tetrahedra, and corners with four equivalent O(11)La3Ti tetrahedra. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one La(3), one La(4), and two equivalent Ti(5) atoms. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to two equivalent La(3), one Ti(4), and one Ti(5) atom. In the seventeenth O site, O(17) is bonded to two equivalent La(3), one Ti(4), and one Ti(5) atom to form distorted OLa2Ti2 tetrahedra that share corners with two equivalent O(10)La3Ti2 square pyramids,  a cornercorner with one O(14)La3Ti tetrahedra, corners with two equivalent O(17)La2Ti2 tetrahedra, and edges with two equivalent O(10)La3Ti2 square pyramids.