Ba2CaGd2CeTi2(CuO7)2 crystallizes in the tetragonal P4mm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(8) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ti(1)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. In the second Ba site, Ba(2) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(9) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ti(2)O6 octahedra, and faces with four equivalent Cu(2)O5 square pyramids. Ca(1) is bonded in a 9-coordinate geometry to one O(6), four equivalent O(3), and four equivalent O(5) atoms. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 9-coordinate geometry to one O(5), four equivalent O(4), and four equivalent O(6) atoms. In the second Gd site, Gd(2) is bonded in a body-centered cubic geometry to four equivalent O(7) and four equivalent O(8) atoms. Ce(1) is bonded in a body-centered cubic geometry to four equivalent O(7) and four equivalent O(9) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(5), and four equivalent O(3) atoms to form TiO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. In the second Ti site, Ti(2) is bonded to one O(2), one O(6), and four equivalent O(4) atoms to form TiO6 octahedra that share corners with four equivalent Ti(2)O6 octahedra,  a cornercorner with one Cu(2)O5 square pyramid, and faces with four equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 11°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1) and four equivalent O(8) atoms to form CuO5 square pyramids that share  a cornercorner with one Ti(1)O6 octahedra, corners with four equivalent Cu(1)O5 square pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the second Cu site, Cu(2) is bonded to one O(2) and four equivalent O(9) atoms to form CuO5 square pyramids that share  a cornercorner with one Ti(2)O6 octahedra, corners with four equivalent Cu(2)O5 square pyramids, and faces with four equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are nine inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Ti(1), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing OBa4TiCu octahedra. The corner-sharing octahedral tilt angles are 15°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(2), one Ti(2), and one Cu(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Ca(1), and two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Ba(2), two equivalent Gd(1), and two equivalent Ti(2) atoms. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to four equivalent Ca(1), one Gd(1), and one Ti(1) atom. In the sixth O site, O(6) is bonded to one Ca(1), four equivalent Gd(1), and one Ti(2) atom to form a mixture of distorted edge and corner-sharing OCaGd4Ti octahedra. The corner-sharing octahedral tilt angles are 12°. In the seventh O site, O(7) is bonded to two equivalent Gd(2) and two equivalent Ce(1) atoms to form OCe2Gd2 tetrahedra that share corners with six equivalent O(9)Ba2Ce2Cu2 octahedra, corners with four equivalent O(7)Ce2Gd2 tetrahedra,  an edgeedge with one O(9)Ba2Ce2Cu2 octahedra, and edges with four equivalent O(7)Ce2Gd2 tetrahedra. The corner-sharing octahedral tilt angles range from 8-71°. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Gd(2), and two equivalent Cu(1) atoms. In the ninth O site, O(9) is bonded to two equivalent Ba(2), two equivalent Ce(1), and two equivalent Cu(2) atoms to form distorted OBa2Ce2Cu2 octahedra that share corners with two equivalent O(9)Ba2Ce2Cu2 octahedra, corners with six equivalent O(7)Ce2Gd2 tetrahedra, edges with two equivalent O(9)Ba2Ce2Cu2 octahedra,  an edgeedge with one O(7)Ce2Gd2 tetrahedra, and faces with four equivalent O(9)Ba2Ce2Cu2 octahedra. The corner-sharing octahedral tilt angles are 10°.
Ba2CaGd2CeTi2(CuO7)2 crystallizes in the tetragonal P4mm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(8) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ti(1)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. All Ba(1)-O(1) bond lengths are 2.79 Å. All Ba(1)-O(3) bond lengths are 3.09 Å. All Ba(1)-O(8) bond lengths are 2.98 Å. In the second Ba site, Ba(2) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(9) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ti(2)O6 octahedra, and faces with four equivalent Cu(2)O5 square pyramids. All Ba(2)-O(2) bond lengths are 2.80 Å. All Ba(2)-O(4) bond lengths are 3.16 Å. All Ba(2)-O(9) bond lengths are 2.92 Å. Ca(1) is bonded in a 9-coordinate geometry to one O(6), four equivalent O(3), and four equivalent O(5) atoms. The Ca(1)-O(6) bond length is 2.33 Å. All Ca(1)-O(3) bond lengths are 2.49 Å. All Ca(1)-O(5) bond lengths are 2.80 Å. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 9-coordinate geometry to one O(5), four equivalent O(4), and four equivalent O(6) atoms. The Gd(1)-O(5) bond length is 2.12 Å. All Gd(1)-O(4) bond lengths are 2.54 Å. All Gd(1)-O(6) bond lengths are 2.78 Å. In the second Gd site, Gd(2) is bonded in a body-centered cubic geometry to four equivalent O(7) and four equivalent O(8) atoms. All Gd(2)-O(7) bond lengths are 2.38 Å. All Gd(2)-O(8) bond lengths are 2.47 Å. Ce(1) is bonded in a body-centered cubic geometry to four equivalent O(7) and four equivalent O(9) atoms. All Ce(1)-O(7) bond lengths are 2.29 Å. All Ce(1)-O(9) bond lengths are 2.52 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(5), and four equivalent O(3) atoms to form TiO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. The Ti(1)-O(1) bond length is 1.86 Å. The Ti(1)-O(5) bond length is 2.20 Å. All Ti(1)-O(3) bond lengths are 1.96 Å. In the second Ti site, Ti(2) is bonded to one O(2), one O(6), and four equivalent O(4) atoms to form TiO6 octahedra that share corners with four equivalent Ti(2)O6 octahedra,  a cornercorner with one Cu(2)O5 square pyramid, and faces with four equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 11°. The Ti(2)-O(2) bond length is 1.86 Å. The Ti(2)-O(6) bond length is 2.09 Å. All Ti(2)-O(4) bond lengths are 1.96 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1) and four equivalent O(8) atoms to form CuO5 square pyramids that share  a cornercorner with one Ti(1)O6 octahedra, corners with four equivalent Cu(1)O5 square pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Cu(1)-O(1) bond length is 2.39 Å. All Cu(1)-O(8) bond lengths are 1.96 Å. In the second Cu site, Cu(2) is bonded to one O(2) and four equivalent O(9) atoms to form CuO5 square pyramids that share  a cornercorner with one Ti(2)O6 octahedra, corners with four equivalent Cu(2)O5 square pyramids, and faces with four equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Cu(2)-O(2) bond length is 2.45 Å. All Cu(2)-O(9) bond lengths are 1.96 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Ti(1), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing OBa4TiCu octahedra. The corner-sharing octahedral tilt angles are 15°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(2), one Ti(2), and one Cu(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Ca(1), and two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Ba(2), two equivalent Gd(1), and two equivalent Ti(2) atoms. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to four equivalent Ca(1), one Gd(1), and one Ti(1) atom. In the sixth O site, O(6) is bonded to one Ca(1), four equivalent Gd(1), and one Ti(2) atom to form a mixture of distorted edge and corner-sharing OCaGd4Ti octahedra. The corner-sharing octahedral tilt angles are 12°. In the seventh O site, O(7) is bonded to two equivalent Gd(2) and two equivalent Ce(1) atoms to form OCe2Gd2 tetrahedra that share corners with six equivalent O(9)Ba2Ce2Cu2 octahedra, corners with four equivalent O(7)Ce2Gd2 tetrahedra,  an edgeedge with one O(9)Ba2Ce2Cu2 octahedra, and edges with four equivalent O(7)Ce2Gd2 tetrahedra. The corner-sharing octahedral tilt angles range from 8-71°. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Gd(2), and two equivalent Cu(1) atoms. In the ninth O site, O(9) is bonded to two equivalent Ba(2), two equivalent Ce(1), and two equivalent Cu(2) atoms to form distorted OBa2Ce2Cu2 octahedra that share corners with two equivalent O(9)Ba2Ce2Cu2 octahedra, corners with six equivalent O(7)Ce2Gd2 tetrahedra, edges with two equivalent O(9)Ba2Ce2Cu2 octahedra,  an edgeedge with one O(7)Ce2Gd2 tetrahedra, and faces with four equivalent O(9)Ba2Ce2Cu2 octahedra. The corner-sharing octahedral tilt angles are 10°.