Th3Sm4O12 crystallizes in the trigonal R3m space group. There are three inequivalent Th sites. In the first Th site, Th(1) is bonded in a body-centered cubic geometry to one O(12), one O(3), three equivalent O(11), and three equivalent O(2) atoms. In the second Th site, Th(2) is bonded in a body-centered cubic geometry to one O(2), one O(4), three equivalent O(1), and three equivalent O(3) atoms. In the third Th site, Th(3) is bonded in a body-centered cubic geometry to one O(1), one O(5), three equivalent O(4), and three equivalent O(6) atoms. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(6), one O(7), and three equivalent O(5) atoms to form corner-sharing SmO5 trigonal bipyramids. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(8), three equivalent O(7), and three equivalent O(9) atoms. In the third Sm site, Sm(3) is bonded in a 7-coordinate geometry to one O(11), three equivalent O(10), and three equivalent O(12) atoms. In the fourth Sm site, Sm(4) is bonded to one O(10), one O(9), and three equivalent O(8) atoms to form corner-sharing SmO5 trigonal bipyramids. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Th(3) and three equivalent Th(2) atoms to form OTh4 tetrahedra that share corners with three equivalent O(6)SmTh3 tetrahedra, corners with three equivalent O(2)Th4 tetrahedra, corners with three equivalent O(3)Th4 tetrahedra, corners with six equivalent O(1)Th4 tetrahedra, edges with three equivalent O(3)Th4 tetrahedra, and edges with three equivalent O(4)Th4 tetrahedra. In the second O site, O(2) is bonded to one Th(2) and three equivalent Th(1) atoms to form OTh4 tetrahedra that share  a cornercorner with one O(4)Th4 tetrahedra, corners with three equivalent O(12)Sm3Th tetrahedra, corners with three equivalent O(11)SmTh3 tetrahedra, corners with three equivalent O(1)Th4 tetrahedra, corners with six equivalent O(2)Th4 tetrahedra, edges with three equivalent O(11)SmTh3 tetrahedra, and edges with three equivalent O(3)Th4 tetrahedra. In the third O site, O(3) is bonded to one Th(1) and three equivalent Th(2) atoms to form OTh4 tetrahedra that share  a cornercorner with one O(12)Sm3Th tetrahedra, corners with three equivalent O(11)SmTh3 tetrahedra, corners with three equivalent O(1)Th4 tetrahedra, corners with three equivalent O(4)Th4 tetrahedra, corners with six equivalent O(3)Th4 tetrahedra, edges with three equivalent O(1)Th4 tetrahedra, and edges with three equivalent O(2)Th4 tetrahedra. In the fourth O site, O(4) is bonded to one Th(2) and three equivalent Th(3) atoms to form OTh4 tetrahedra that share  a cornercorner with one O(2)Th4 tetrahedra, corners with three equivalent O(6)SmTh3 tetrahedra, corners with three equivalent O(3)Th4 tetrahedra, corners with six equivalent O(4)Th4 tetrahedra, edges with three equivalent O(6)SmTh3 tetrahedra, and edges with three equivalent O(1)Th4 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Th(3) and three equivalent Sm(1) atoms. In the sixth O site, O(6) is bonded to three equivalent Th(3) and one Sm(1) atom to form OSmTh3 tetrahedra that share  a cornercorner with one O(7)Sm4 tetrahedra, corners with three equivalent O(1)Th4 tetrahedra, corners with three equivalent O(4)Th4 tetrahedra, corners with six equivalent O(6)SmTh3 tetrahedra, and edges with three equivalent O(4)Th4 tetrahedra. In the seventh O site, O(7) is bonded to one Sm(1) and three equivalent Sm(2) atoms to form distorted OSm4 tetrahedra that share  a cornercorner with one O(6)SmTh3 tetrahedra, corners with three equivalent O(8)Sm4 tetrahedra, corners with three equivalent O(9)Sm4 tetrahedra, corners with six equivalent O(7)Sm4 tetrahedra, and edges with three equivalent O(9)Sm4 tetrahedra. In the eighth O site, O(8) is bonded to one Sm(2) and three equivalent Sm(4) atoms to form a mixture of distorted corner and edge-sharing OSm4 tetrahedra. In the ninth O site, O(9) is bonded to one Sm(4) and three equivalent Sm(2) atoms to form a mixture of corner and edge-sharing OSm4 tetrahedra. In the tenth O site, O(10) is bonded to one Sm(4) and three equivalent Sm(3) atoms to form distorted OSm4 tetrahedra that share  a cornercorner with one O(9)Sm4 tetrahedra, corners with three equivalent O(12)Sm3Th tetrahedra, corners with three equivalent O(8)Sm4 tetrahedra, corners with three equivalent O(11)SmTh3 tetrahedra, corners with six equivalent O(10)Sm4 tetrahedra, and edges with three equivalent O(12)Sm3Th tetrahedra. In the eleventh O site, O(11) is bonded to three equivalent Th(1) and one Sm(3) atom to form OSmTh3 tetrahedra that share corners with three equivalent O(10)Sm4 tetrahedra, corners with three equivalent O(2)Th4 tetrahedra, corners with three equivalent O(3)Th4 tetrahedra, corners with six equivalent O(11)SmTh3 tetrahedra, edges with three equivalent O(12)Sm3Th tetrahedra, and edges with three equivalent O(2)Th4 tetrahedra. In the twelfth O site, O(12) is bonded to one Th(1) and three equivalent Sm(3) atoms to form OSm3Th tetrahedra that share  a cornercorner with one O(3)Th4 tetrahedra, corners with three equivalent O(10)Sm4 tetrahedra, corners with three equivalent O(2)Th4 tetrahedra, corners with six equivalent O(12)Sm3Th tetrahedra, edges with three equivalent O(10)Sm4 tetrahedra, and edges with three equivalent O(11)SmTh3 tetrahedra.
Th3Sm4O12 crystallizes in the trigonal R3m space group. There are three inequivalent Th sites. In the first Th site, Th(1) is bonded in a body-centered cubic geometry to one O(12), one O(3), three equivalent O(11), and three equivalent O(2) atoms. The Th(1)-O(12) bond length is 2.37 Å. The Th(1)-O(3) bond length is 2.56 Å. All Th(1)-O(11) bond lengths are 2.37 Å. All Th(1)-O(2) bond lengths are 2.43 Å. In the second Th site, Th(2) is bonded in a body-centered cubic geometry to one O(2), one O(4), three equivalent O(1), and three equivalent O(3) atoms. The Th(2)-O(2) bond length is 2.38 Å. The Th(2)-O(4) bond length is 2.54 Å. All Th(2)-O(1) bond lengths are 2.44 Å. All Th(2)-O(3) bond lengths are 2.37 Å. In the third Th site, Th(3) is bonded in a body-centered cubic geometry to one O(1), one O(5), three equivalent O(4), and three equivalent O(6) atoms. The Th(3)-O(1) bond length is 2.36 Å. The Th(3)-O(5) bond length is 2.86 Å. All Th(3)-O(4) bond lengths are 2.38 Å. All Th(3)-O(6) bond lengths are 2.42 Å. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(6), one O(7), and three equivalent O(5) atoms to form corner-sharing SmO5 trigonal bipyramids. The Sm(1)-O(6) bond length is 2.40 Å. The Sm(1)-O(7) bond length is 2.21 Å. All Sm(1)-O(5) bond lengths are 2.29 Å. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(8), three equivalent O(7), and three equivalent O(9) atoms. The Sm(2)-O(8) bond length is 2.62 Å. All Sm(2)-O(7) bond lengths are 2.59 Å. All Sm(2)-O(9) bond lengths are 2.36 Å. In the third Sm site, Sm(3) is bonded in a 7-coordinate geometry to one O(11), three equivalent O(10), and three equivalent O(12) atoms. The Sm(3)-O(11) bond length is 2.37 Å. All Sm(3)-O(10) bond lengths are 2.59 Å. All Sm(3)-O(12) bond lengths are 2.37 Å. In the fourth Sm site, Sm(4) is bonded to one O(10), one O(9), and three equivalent O(8) atoms to form corner-sharing SmO5 trigonal bipyramids. The Sm(4)-O(10) bond length is 2.22 Å. The Sm(4)-O(9) bond length is 2.36 Å. All Sm(4)-O(8) bond lengths are 2.30 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Th(3) and three equivalent Th(2) atoms to form OTh4 tetrahedra that share corners with three equivalent O(6)SmTh3 tetrahedra, corners with three equivalent O(2)Th4 tetrahedra, corners with three equivalent O(3)Th4 tetrahedra, corners with six equivalent O(1)Th4 tetrahedra, edges with three equivalent O(3)Th4 tetrahedra, and edges with three equivalent O(4)Th4 tetrahedra. In the second O site, O(2) is bonded to one Th(2) and three equivalent Th(1) atoms to form OTh4 tetrahedra that share  a cornercorner with one O(4)Th4 tetrahedra, corners with three equivalent O(12)Sm3Th tetrahedra, corners with three equivalent O(11)SmTh3 tetrahedra, corners with three equivalent O(1)Th4 tetrahedra, corners with six equivalent O(2)Th4 tetrahedra, edges with three equivalent O(11)SmTh3 tetrahedra, and edges with three equivalent O(3)Th4 tetrahedra. In the third O site, O(3) is bonded to one Th(1) and three equivalent Th(2) atoms to form OTh4 tetrahedra that share  a cornercorner with one O(12)Sm3Th tetrahedra, corners with three equivalent O(11)SmTh3 tetrahedra, corners with three equivalent O(1)Th4 tetrahedra, corners with three equivalent O(4)Th4 tetrahedra, corners with six equivalent O(3)Th4 tetrahedra, edges with three equivalent O(1)Th4 tetrahedra, and edges with three equivalent O(2)Th4 tetrahedra. In the fourth O site, O(4) is bonded to one Th(2) and three equivalent Th(3) atoms to form OTh4 tetrahedra that share  a cornercorner with one O(2)Th4 tetrahedra, corners with three equivalent O(6)SmTh3 tetrahedra, corners with three equivalent O(3)Th4 tetrahedra, corners with six equivalent O(4)Th4 tetrahedra, edges with three equivalent O(6)SmTh3 tetrahedra, and edges with three equivalent O(1)Th4 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Th(3) and three equivalent Sm(1) atoms. In the sixth O site, O(6) is bonded to three equivalent Th(3) and one Sm(1) atom to form OSmTh3 tetrahedra that share  a cornercorner with one O(7)Sm4 tetrahedra, corners with three equivalent O(1)Th4 tetrahedra, corners with three equivalent O(4)Th4 tetrahedra, corners with six equivalent O(6)SmTh3 tetrahedra, and edges with three equivalent O(4)Th4 tetrahedra. In the seventh O site, O(7) is bonded to one Sm(1) and three equivalent Sm(2) atoms to form distorted OSm4 tetrahedra that share  a cornercorner with one O(6)SmTh3 tetrahedra, corners with three equivalent O(8)Sm4 tetrahedra, corners with three equivalent O(9)Sm4 tetrahedra, corners with six equivalent O(7)Sm4 tetrahedra, and edges with three equivalent O(9)Sm4 tetrahedra. In the eighth O site, O(8) is bonded to one Sm(2) and three equivalent Sm(4) atoms to form a mixture of distorted corner and edge-sharing OSm4 tetrahedra. In the ninth O site, O(9) is bonded to one Sm(4) and three equivalent Sm(2) atoms to form a mixture of corner and edge-sharing OSm4 tetrahedra. In the tenth O site, O(10) is bonded to one Sm(4) and three equivalent Sm(3) atoms to form distorted OSm4 tetrahedra that share  a cornercorner with one O(9)Sm4 tetrahedra, corners with three equivalent O(12)Sm3Th tetrahedra, corners with three equivalent O(8)Sm4 tetrahedra, corners with three equivalent O(11)SmTh3 tetrahedra, corners with six equivalent O(10)Sm4 tetrahedra, and edges with three equivalent O(12)Sm3Th tetrahedra. In the eleventh O site, O(11) is bonded to three equivalent Th(1) and one Sm(3) atom to form OSmTh3 tetrahedra that share corners with three equivalent O(10)Sm4 tetrahedra, corners with three equivalent O(2)Th4 tetrahedra, corners with three equivalent O(3)Th4 tetrahedra, corners with six equivalent O(11)SmTh3 tetrahedra, edges with three equivalent O(12)Sm3Th tetrahedra, and edges with three equivalent O(2)Th4 tetrahedra. In the twelfth O site, O(12) is bonded to one Th(1) and three equivalent Sm(3) atoms to form OSm3Th tetrahedra that share  a cornercorner with one O(3)Th4 tetrahedra, corners with three equivalent O(10)Sm4 tetrahedra, corners with three equivalent O(2)Th4 tetrahedra, corners with six equivalent O(12)Sm3Th tetrahedra, edges with three equivalent O(10)Sm4 tetrahedra, and edges with three equivalent O(11)SmTh3 tetrahedra.