K3NaSi3(SnO6)2 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. Sn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form SnO6 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 Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-35°. There are two inequivalent O sites. In the first O site, O(2) is bonded to two equivalent K(1), one Na(1), one Sn(1), and one Si(1) atom to form a mixture of distorted edge, corner, and face-sharing OK2NaSiSn trigonal bipyramids. In the second O site, O(1) is bonded in a 4-coordinate geometry to two equivalent K(1), one Sn(1), and one Si(1) atom.
K3NaSi3(SnO6)2 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 (2.76 Å) and two longer (2.89 Å) K(1)-O(1) bond lengths. There are two shorter (2.59 Å) and two longer (2.69 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 2.60 Å. Sn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form SnO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. All Sn(1)-O(1) bond lengths are 2.07 Å. All Sn(1)-O(2) bond lengths are 2.14 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 Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-35°. Both Si(1)-O(1) bond lengths are 1.65 Å. Both Si(1)-O(2) bond lengths are 1.66 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 Sn(1), and one Si(1) atom to form a mixture of distorted edge, corner, and face-sharing OK2NaSiSn trigonal bipyramids. In the second O site, O(1) is bonded in a 4-coordinate geometry to two equivalent K(1), one Sn(1), and one Si(1) atom.