K2ThO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted KO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with two equivalent Th(1)O6 octahedra, corners with two equivalent Th(2)O6 octahedra, edges with two equivalent K(2)O6 octahedra, edges with two equivalent Th(1)O6 octahedra, edges with two equivalent Th(2)O6 octahedra, edges with three equivalent K(1)O6 octahedra, and edges with three equivalent K(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-18°. In the second K site, K(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted KO6 octahedra that share corners with two equivalent K(3)O6 octahedra, corners with four equivalent K(1)O6 octahedra, edges with two equivalent K(3)O6 octahedra, edges with three equivalent Th(1)O6 octahedra, edges with three equivalent Th(2)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-19°. In the third K site, K(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted KO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with two equivalent Th(1)O6 octahedra, corners with two equivalent Th(2)O6 octahedra, edges with two equivalent K(2)O6 octahedra, edges with two equivalent Th(1)O6 octahedra, edges with two equivalent Th(2)O6 octahedra, and edges with six equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-19°. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form ThO6 octahedra that share corners with two equivalent K(3)O6 octahedra, corners with four equivalent K(1)O6 octahedra, edges with two equivalent K(3)O6 octahedra, edges with three equivalent K(2)O6 octahedra, edges with three equivalent Th(2)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-16°. In the second Th site, Th(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form ThO6 octahedra that share corners with two equivalent K(3)O6 octahedra, corners with four equivalent K(1)O6 octahedra, edges with two equivalent K(3)O6 octahedra, edges with three equivalent K(2)O6 octahedra, edges with three equivalent Th(1)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-16°. There are three inequivalent O sites. In the first O site, O(3) is bonded to one K(2), one K(3), two equivalent K(1), one Th(1), and one Th(2) atom to form a mixture of distorted corner and edge-sharing OK4Th2 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the second O site, O(1) is bonded to one K(2), one K(3), two equivalent K(1), one Th(1), and one Th(2) atom to form a mixture of distorted corner and edge-sharing OK4Th2 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the third O site, O(2) is bonded to one K(2), one K(3), two equivalent K(1), one Th(1), and one Th(2) atom to form a mixture of distorted corner and edge-sharing OK4Th2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°.
K2ThO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted KO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with two equivalent Th(1)O6 octahedra, corners with two equivalent Th(2)O6 octahedra, edges with two equivalent K(2)O6 octahedra, edges with two equivalent Th(1)O6 octahedra, edges with two equivalent Th(2)O6 octahedra, edges with three equivalent K(1)O6 octahedra, and edges with three equivalent K(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-18°. There is one shorter (2.68 Å) and one longer (3.01 Å) K(1)-O(1) bond length. There is one shorter (2.90 Å) and one longer (2.92 Å) K(1)-O(2) bond length. There is one shorter (2.69 Å) and one longer (3.02 Å) K(1)-O(3) bond length. In the second K site, K(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted KO6 octahedra that share corners with two equivalent K(3)O6 octahedra, corners with four equivalent K(1)O6 octahedra, edges with two equivalent K(3)O6 octahedra, edges with three equivalent Th(1)O6 octahedra, edges with three equivalent Th(2)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-19°. Both K(2)-O(1) bond lengths are 2.75 Å. Both K(2)-O(2) bond lengths are 2.75 Å. Both K(2)-O(3) bond lengths are 2.75 Å. In the third K site, K(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted KO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with two equivalent Th(1)O6 octahedra, corners with two equivalent Th(2)O6 octahedra, edges with two equivalent K(2)O6 octahedra, edges with two equivalent Th(1)O6 octahedra, edges with two equivalent Th(2)O6 octahedra, and edges with six equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-19°. Both K(3)-O(1) bond lengths are 2.99 Å. Both K(3)-O(2) bond lengths are 2.64 Å. Both K(3)-O(3) bond lengths are 2.98 Å. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form ThO6 octahedra that share corners with two equivalent K(3)O6 octahedra, corners with four equivalent K(1)O6 octahedra, edges with two equivalent K(3)O6 octahedra, edges with three equivalent K(2)O6 octahedra, edges with three equivalent Th(2)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-16°. Both Th(1)-O(1) bond lengths are 2.35 Å. Both Th(1)-O(2) bond lengths are 2.36 Å. Both Th(1)-O(3) bond lengths are 2.35 Å. In the second Th site, Th(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form ThO6 octahedra that share corners with two equivalent K(3)O6 octahedra, corners with four equivalent K(1)O6 octahedra, edges with two equivalent K(3)O6 octahedra, edges with three equivalent K(2)O6 octahedra, edges with three equivalent Th(1)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-16°. Both Th(2)-O(1) bond lengths are 2.35 Å. Both Th(2)-O(2) bond lengths are 2.35 Å. Both Th(2)-O(3) bond lengths are 2.35 Å. There are three inequivalent O sites. In the first O site, O(3) is bonded to one K(2), one K(3), two equivalent K(1), one Th(1), and one Th(2) atom to form a mixture of distorted corner and edge-sharing OK4Th2 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the second O site, O(1) is bonded to one K(2), one K(3), two equivalent K(1), one Th(1), and one Th(2) atom to form a mixture of distorted corner and edge-sharing OK4Th2 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the third O site, O(2) is bonded to one K(2), one K(3), two equivalent K(1), one Th(1), and one Th(2) atom to form a mixture of distorted corner and edge-sharing OK4Th2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°.