Ca2Ti2O5 crystallizes in the orthorhombic Ima2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(3), three equivalent O(2), and four equivalent O(1) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form TiO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 11°. In the second Ti site, Ti(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form TiO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Ti(1) atoms to form distorted OCa4Ti2 octahedra that share corners with two equivalent O(1)Ca4Ti2 octahedra, corners with four equivalent O(3)Ca2Ti2 tetrahedra, edges with two equivalent O(1)Ca4Ti2 octahedra, and faces with four equivalent O(1)Ca4Ti2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded to two equivalent Ca(1) and two equivalent Ti(2) atoms to form distorted OCa2Ti2 tetrahedra that share corners with eight equivalent O(1)Ca4Ti2 octahedra and corners with two equivalent O(3)Ca2Ti2 tetrahedra. The corner-sharing octahedral tilt angles range from 20-81°.
Ca2Ti2O5 crystallizes in the orthorhombic Ima2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(3), three equivalent O(2), and four equivalent O(1) atoms. The Ca(1)-O(3) bond length is 2.43 Å. There are a spread of Ca(1)-O(2) bond distances ranging from 2.39-2.89 Å. There are a spread of Ca(1)-O(1) bond distances ranging from 2.53-2.63 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(1) atoms to form TiO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 11°. Both Ti(1)-O(2) bond lengths are 2.08 Å. All Ti(1)-O(1) bond lengths are 1.98 Å. In the second Ti site, Ti(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form TiO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. Both Ti(2)-O(2) bond lengths are 1.90 Å. There is one shorter (1.97 Å) and one longer (1.98 Å) Ti(2)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Ti(1) atoms to form distorted OCa4Ti2 octahedra that share corners with two equivalent O(1)Ca4Ti2 octahedra, corners with four equivalent O(3)Ca2Ti2 tetrahedra, edges with two equivalent O(1)Ca4Ti2 octahedra, and faces with four equivalent O(1)Ca4Ti2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded to two equivalent Ca(1) and two equivalent Ti(2) atoms to form distorted OCa2Ti2 tetrahedra that share corners with eight equivalent O(1)Ca4Ti2 octahedra and corners with two equivalent O(3)Ca2Ti2 tetrahedra. The corner-sharing octahedral tilt angles range from 20-81°.