K3NaTi2(SiO4)3 crystallizes in the trigonal R-3c space group. K(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. Na(1) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. Ti(1) is bonded to three equivalent O(1) and three equivalent O(2) 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 four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-35°. There are two inequivalent O sites. In the first O site, O(2) is bonded to two equivalent K(1), one Na(1), one Ti(1), and one Si(1) atom to form a mixture of distorted face, corner, and edge-sharing OK2NaTiSi trigonal bipyramids. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Ti(1), and one Si(1) atom.
K3NaTi2(SiO4)3 crystallizes in the trigonal R-3c space group. K(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. There are two shorter (2.73 Å) and two longer (2.93 Å) K(1)-O(1) bond lengths. There are two shorter (2.55 Å) and two longer (2.68 Å) K(1)-O(2) bond lengths. Na(1) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. All Na(1)-O(2) bond lengths are 2.54 Å. Ti(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form TiO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. All Ti(1)-O(1) bond lengths are 1.92 Å. All Ti(1)-O(2) bond lengths are 2.10 Å. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-35°. Both Si(1)-O(1) bond lengths are 1.67 Å. Both Si(1)-O(2) bond lengths are 1.64 Å. There are two inequivalent O sites. In the first O site, O(2) is bonded to two equivalent K(1), one Na(1), one Ti(1), and one Si(1) atom to form a mixture of distorted face, corner, and edge-sharing OK2NaTiSi trigonal bipyramids. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Ti(1), and one Si(1) atom.