CaTi5O7 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-9°. In the second Ti site, Ti(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-38°. In the third Ti site, Ti(3) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are four inequivalent O sites. In the first O site, O(3) is bonded to one Ca(1), one Ti(3), two equivalent Ti(1), and two equivalent Ti(2) atoms to form distorted OCaTi5 octahedra that share corners with two equivalent O(3)CaTi5 octahedra, corners with two equivalent O(1)Ti6 octahedra, corners with four equivalent O(2)Ca2Ti3 trigonal bipyramids, edges with two equivalent O(3)CaTi5 octahedra, edges with five equivalent O(1)Ti6 octahedra, and edges with three equivalent O(2)Ca2Ti3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-49°. In the second O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Ti(2) atoms. In the third O site, O(1) is bonded to one Ti(2), two equivalent Ti(3), and three equivalent Ti(1) atoms to form OTi6 octahedra that share corners with two equivalent O(3)CaTi5 octahedra, corners with two equivalent O(1)Ti6 octahedra,  a cornercorner with one O(2)Ca2Ti3 trigonal bipyramid, edges with five equivalent O(3)CaTi5 octahedra, edges with five equivalent O(1)Ti6 octahedra, and edges with two equivalent O(2)Ca2Ti3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-12°. In the fourth O site, O(2) is bonded to two equivalent Ca(1), one Ti(1), and two equivalent Ti(2) atoms to form distorted OCa2Ti3 trigonal bipyramids that share  a cornercorner with one O(1)Ti6 octahedra, corners with four equivalent O(3)CaTi5 octahedra, corners with two equivalent O(2)Ca2Ti3 trigonal bipyramids, edges with two equivalent O(1)Ti6 octahedra, edges with three equivalent O(3)CaTi5 octahedra, and edges with three equivalent O(2)Ca2Ti3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-41°.
CaTi5O7 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. Both Ca(1)-O(3) bond lengths are 2.67 Å. Both Ca(1)-O(4) bond lengths are 2.34 Å. All Ca(1)-O(2) bond lengths are 2.40 Å. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-9°. The Ti(1)-O(2) bond length is 2.08 Å. Both Ti(1)-O(3) bond lengths are 2.08 Å. There is one shorter (2.15 Å) and two longer (2.16 Å) Ti(1)-O(1) bond lengths. In the second Ti site, Ti(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 7-38°. The Ti(2)-O(1) bond length is 2.09 Å. The Ti(2)-O(4) bond length is 1.97 Å. Both Ti(2)-O(2) bond lengths are 2.10 Å. Both Ti(2)-O(3) bond lengths are 2.09 Å. In the third Ti site, Ti(3) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 9°. Both Ti(3)-O(3) bond lengths are 2.25 Å. All Ti(3)-O(1) bond lengths are 2.18 Å. There are four inequivalent O sites. In the first O site, O(3) is bonded to one Ca(1), one Ti(3), two equivalent Ti(1), and two equivalent Ti(2) atoms to form distorted OCaTi5 octahedra that share corners with two equivalent O(3)CaTi5 octahedra, corners with two equivalent O(1)Ti6 octahedra, corners with four equivalent O(2)Ca2Ti3 trigonal bipyramids, edges with two equivalent O(3)CaTi5 octahedra, edges with five equivalent O(1)Ti6 octahedra, and edges with three equivalent O(2)Ca2Ti3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-49°. In the second O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Ti(2) atoms. In the third O site, O(1) is bonded to one Ti(2), two equivalent Ti(3), and three equivalent Ti(1) atoms to form OTi6 octahedra that share corners with two equivalent O(3)CaTi5 octahedra, corners with two equivalent O(1)Ti6 octahedra,  a cornercorner with one O(2)Ca2Ti3 trigonal bipyramid, edges with five equivalent O(3)CaTi5 octahedra, edges with five equivalent O(1)Ti6 octahedra, and edges with two equivalent O(2)Ca2Ti3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-12°. In the fourth O site, O(2) is bonded to two equivalent Ca(1), one Ti(1), and two equivalent Ti(2) atoms to form distorted OCa2Ti3 trigonal bipyramids that share  a cornercorner with one O(1)Ti6 octahedra, corners with four equivalent O(3)CaTi5 octahedra, corners with two equivalent O(2)Ca2Ti3 trigonal bipyramids, edges with two equivalent O(1)Ti6 octahedra, edges with three equivalent O(3)CaTi5 octahedra, and edges with three equivalent O(2)Ca2Ti3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-41°.