Rb2Ti(SiO3)3 crystallizes in the hexagonal P6_3/m space group. Rb(1) is bonded in a 9-coordinate geometry to three equivalent O(2) and six equivalent O(1) atoms. Ti(1) is bonded to six equivalent O(1) atoms to form TiO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 34°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Rb(1), one Ti(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Rb(1) and two equivalent Si(1) atoms.
Rb2Ti(SiO3)3 crystallizes in the hexagonal P6_3/m space group. Rb(1) is bonded in a 9-coordinate geometry to three equivalent O(2) and six equivalent O(1) atoms. All Rb(1)-O(2) bond lengths are 3.19 Å. There are three shorter (3.01 Å) and three longer (3.14 Å) Rb(1)-O(1) bond lengths. Ti(1) is bonded to six equivalent O(1) atoms to form TiO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. All Ti(1)-O(1) bond lengths are 1.98 Å. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 34°. Both Si(1)-O(1) bond lengths are 1.62 Å. There is one shorter (1.66 Å) and one longer (1.68 Å) Si(1)-O(2) bond length. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Rb(1), one Ti(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Rb(1) and two equivalent Si(1) atoms.