Ca2TiTa2O8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(4), and four equivalent O(3) atoms. Ti(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with eight equivalent Ta(1)O6 octahedra and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra and edges with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Ti(1), and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one Ta(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Ca(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OCa3Ta trigonal pyramids.
Ca2TiTa2O8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(4), and four equivalent O(3) atoms. The Ca(1)-O(1) bond length is 2.93 Å. There are a spread of Ca(1)-O(4) bond distances ranging from 2.23-2.35 Å. There are a spread of Ca(1)-O(3) bond distances ranging from 2.21-2.96 Å. Ti(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with eight equivalent Ta(1)O6 octahedra and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. Both Ti(1)-O(1) bond lengths are 2.21 Å. There are two shorter (2.09 Å) and two longer (2.18 Å) Ti(1)-O(2) bond lengths. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with four equivalent Ti(1)O6 octahedra and edges with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. The Ta(1)-O(2) bond length is 1.93 Å. The Ta(1)-O(4) bond length is 1.91 Å. There is one shorter (2.02 Å) and one longer (2.15 Å) Ta(1)-O(1) bond length. There is one shorter (2.04 Å) and one longer (2.22 Å) Ta(1)-O(3) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Ti(1), and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one Ta(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Ca(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OCa3Ta trigonal pyramids.