CaUTi2O7 crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms to form distorted CaO8 hexagonal bipyramids that share edges with two equivalent Ca(1)O8 hexagonal bipyramids, edges with four equivalent U(1)O8 hexagonal bipyramids, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Ti(2)O6 octahedra. U(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted UO8 hexagonal bipyramids that share edges with two equivalent U(1)O8 hexagonal bipyramids, edges with four equivalent Ca(1)O8 hexagonal bipyramids, edges with two equivalent Ti(2)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Ti(2)O6 octahedra, edges with two equivalent Ca(1)O8 hexagonal bipyramids, and edges with four equivalent U(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 49-51°. In the second Ti site, Ti(2) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, edges with two equivalent U(1)O8 hexagonal bipyramids, and edges with four equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 44-49°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and two equivalent U(1) atoms to form OCa2U2 tetrahedra that share corners with two equivalent O(2)U2Ti2 tetrahedra, corners with four equivalent O(1)Ca2U2 tetrahedra, corners with eight equivalent O(4)CaUTi2 tetrahedra,  an edgeedge with one O(2)U2Ti2 tetrahedra, and edges with four equivalent O(4)CaUTi2 tetrahedra. In the second O site, O(2) is bonded to two equivalent U(1) and two equivalent Ti(1) atoms to form distorted OU2Ti2 tetrahedra that share corners with two equivalent O(1)Ca2U2 tetrahedra, corners with four equivalent O(2)U2Ti2 tetrahedra, corners with eight equivalent O(4)CaUTi2 tetrahedra,  an edgeedge with one O(1)Ca2U2 tetrahedra, and edges with four equivalent O(4)CaUTi2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Ti(2) atoms. In the fourth O site, O(4) is bonded to one Ca(1), one U(1), one Ti(1), and one Ti(2) atom to form distorted OCaUTi2 tetrahedra that share corners with two equivalent O(1)Ca2U2 tetrahedra, corners with two equivalent O(2)U2Ti2 tetrahedra, corners with eight equivalent O(4)CaUTi2 tetrahedra,  an edgeedge with one O(1)Ca2U2 tetrahedra,  an edgeedge with one O(2)U2Ti2 tetrahedra, and edges with two equivalent O(4)CaUTi2 tetrahedra.
CaUTi2O7 crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms to form distorted CaO8 hexagonal bipyramids that share edges with two equivalent Ca(1)O8 hexagonal bipyramids, edges with four equivalent U(1)O8 hexagonal bipyramids, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Ti(2)O6 octahedra. Both Ca(1)-O(1) bond lengths are 2.26 Å. Both Ca(1)-O(3) bond lengths are 2.55 Å. All Ca(1)-O(4) bond lengths are 2.57 Å. U(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted UO8 hexagonal bipyramids that share edges with two equivalent U(1)O8 hexagonal bipyramids, edges with four equivalent Ca(1)O8 hexagonal bipyramids, edges with two equivalent Ti(2)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. Both U(1)-O(1) bond lengths are 2.17 Å. Both U(1)-O(2) bond lengths are 2.50 Å. All U(1)-O(4) bond lengths are 2.45 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Ti(2)O6 octahedra, edges with two equivalent Ca(1)O8 hexagonal bipyramids, and edges with four equivalent U(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 49-51°. Both Ti(1)-O(2) bond lengths are 1.98 Å. All Ti(1)-O(4) bond lengths are 1.98 Å. In the second Ti site, Ti(2) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, edges with two equivalent U(1)O8 hexagonal bipyramids, and edges with four equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 44-49°. Both Ti(2)-O(3) bond lengths are 1.97 Å. All Ti(2)-O(4) bond lengths are 1.99 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and two equivalent U(1) atoms to form OCa2U2 tetrahedra that share corners with two equivalent O(2)U2Ti2 tetrahedra, corners with four equivalent O(1)Ca2U2 tetrahedra, corners with eight equivalent O(4)CaUTi2 tetrahedra,  an edgeedge with one O(2)U2Ti2 tetrahedra, and edges with four equivalent O(4)CaUTi2 tetrahedra. In the second O site, O(2) is bonded to two equivalent U(1) and two equivalent Ti(1) atoms to form distorted OU2Ti2 tetrahedra that share corners with two equivalent O(1)Ca2U2 tetrahedra, corners with four equivalent O(2)U2Ti2 tetrahedra, corners with eight equivalent O(4)CaUTi2 tetrahedra,  an edgeedge with one O(1)Ca2U2 tetrahedra, and edges with four equivalent O(4)CaUTi2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Ti(2) atoms. In the fourth O site, O(4) is bonded to one Ca(1), one U(1), one Ti(1), and one Ti(2) atom to form distorted OCaUTi2 tetrahedra that share corners with two equivalent O(1)Ca2U2 tetrahedra, corners with two equivalent O(2)U2Ti2 tetrahedra, corners with eight equivalent O(4)CaUTi2 tetrahedra,  an edgeedge with one O(1)Ca2U2 tetrahedra,  an edgeedge with one O(2)U2Ti2 tetrahedra, and edges with two equivalent O(4)CaUTi2 tetrahedra.