Sm7Ti4(Se2O)6 crystallizes in the monoclinic Cm space group. There are seven inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to one Se(5), two equivalent Se(12), two equivalent Se(2), one O(4), and two equivalent O(2) atoms. In the second Sm site, Sm(2) is bonded in a 3-coordinate geometry to one Se(6), two equivalent Se(1), two equivalent Se(11), one O(3), and two equivalent O(1) atoms. In the third Sm site, Sm(3) is bonded in a 9-coordinate geometry to one Se(2), one Se(4), two equivalent Se(5), two equivalent Se(9), one O(1), and two equivalent O(3) atoms. In the fourth Sm site, Sm(4) is bonded in a 3-coordinate geometry to one Se(1), one Se(3), two equivalent Se(10), two equivalent Se(6), one O(2), and two equivalent O(4) atoms. In the fifth Sm site, Sm(5) is bonded in a 3-coordinate geometry to one Se(8), two equivalent Se(12), two equivalent Se(4), one O(5), and two equivalent O(6) atoms. In the sixth Sm site, Sm(6) is bonded in a 3-coordinate geometry to one Se(7), two equivalent Se(11), two equivalent Se(3), one O(6), and two equivalent O(5) atoms. In the seventh Sm site, Sm(7) is bonded in a 7-coordinate geometry to one Se(1), one Se(11), one Se(8), two equivalent Se(10), and two equivalent Se(7) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one Se(9), two equivalent Se(4), two equivalent Se(7), and one O(5) atom to form distorted edge-sharing TiSe5O octahedra. In the second Ti site, Ti(2) is bonded in a distorted single-bond geometry to one Se(10), two equivalent Se(3), two equivalent Se(8), and one O(6) atom. In the third Ti site, Ti(3) is bonded in a distorted linear geometry to two equivalent Se(5), two equivalent Se(6), one O(1), and one O(2) atom. In the fourth Ti site, Ti(4) is bonded in a distorted linear geometry to two equivalent Se(1), two equivalent Se(2), one O(3), and one O(4) atom. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one Sm(4), one Sm(7), two equivalent Sm(2), and two equivalent Ti(4) atoms. In the second Se site, Se(2) is bonded in a distorted pentagonal planar geometry to one Sm(3), two equivalent Sm(1), and two equivalent Ti(4) atoms. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one Sm(4), two equivalent Sm(6), and two equivalent Ti(2) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to one Sm(3), two equivalent Sm(5), and two equivalent Ti(1) atoms. In the fifth Se site, Se(5) is bonded in a distorted pentagonal planar geometry to one Sm(1), two equivalent Sm(3), and two equivalent Ti(3) atoms. In the sixth Se site, Se(6) is bonded in a distorted pentagonal planar geometry to one Sm(2), two equivalent Sm(4), and two equivalent Ti(3) atoms. In the seventh Se site, Se(7) is bonded in a 5-coordinate geometry to one Sm(6), two equivalent Sm(7), and two equivalent Ti(1) atoms. In the eighth Se site, Se(8) is bonded in a 4-coordinate geometry to one Sm(5), one Sm(7), and two equivalent Ti(2) atoms. In the ninth Se site, Se(9) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Sm(3) and one Ti(1) atom. In the tenth Se site, Se(10) is bonded to two equivalent Sm(4), two equivalent Sm(7), and one Ti(2) atom to form distorted SeSm4Ti trigonal bipyramids that share corners with two equivalent Se(11)Sm5 square pyramids,  a cornercorner with one O(6)Sm3Ti tetrahedra, corners with two equivalent O(2)Sm3Ti tetrahedra, corners with two equivalent O(4)Sm3Ti tetrahedra,  an edgeedge with one O(4)Sm3Ti tetrahedra, and edges with two equivalent Se(10)Sm4Ti trigonal bipyramids. In the eleventh Se site, Se(11) is bonded to one Sm(7), two equivalent Sm(2), and two equivalent Sm(6) atoms to form distorted SeSm5 square pyramids that share corners with two equivalent O(1)Sm3Ti tetrahedra, corners with two equivalent O(3)Sm3Ti tetrahedra, corners with two equivalent O(5)Sm3Ti tetrahedra, corners with two equivalent O(6)Sm3Ti tetrahedra, corners with two equivalent Se(10)Sm4Ti trigonal bipyramids, edges with two equivalent Se(11)Sm5 square pyramids,  an edgeedge with one O(1)Sm3Ti tetrahedra, and  an edgeedge with one O(5)Sm3Ti tetrahedra. In the twelfth Se site, Se(12) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sm(1) and two equivalent Sm(5) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Sm(3), two equivalent Sm(2), and one Ti(3) atom to form distorted OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids,  a cornercorner with one O(2)Sm3Ti tetrahedra, corners with two equivalent O(1)Sm3Ti tetrahedra,  an edgeedge with one Se(11)Sm5 square pyramid, and edges with two equivalent O(3)Sm3Ti tetrahedra. In the second O site, O(2) is bonded to one Sm(4), two equivalent Sm(1), and one Ti(3) atom to form OSm3Ti tetrahedra that share  a cornercorner with one O(1)Sm3Ti tetrahedra, corners with two equivalent O(2)Sm3Ti tetrahedra, corners with two equivalent Se(10)Sm4Ti trigonal bipyramids, and edges with two equivalent O(4)Sm3Ti tetrahedra. In the third O site, O(3) is bonded to one Sm(2), two equivalent Sm(3), and one Ti(4) atom to form OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids,  a cornercorner with one O(4)Sm3Ti tetrahedra, corners with two equivalent O(3)Sm3Ti tetrahedra, and edges with two equivalent O(1)Sm3Ti tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), two equivalent Sm(4), and one Ti(4) atom to form distorted OSm3Ti tetrahedra that share  a cornercorner with one O(3)Sm3Ti tetrahedra, corners with two equivalent O(4)Sm3Ti tetrahedra, corners with two equivalent Se(10)Sm4Ti trigonal bipyramids, edges with two equivalent O(2)Sm3Ti tetrahedra, and  an edgeedge with one Se(10)Sm4Ti trigonal bipyramid. In the fifth O site, O(5) is bonded to one Sm(5), two equivalent Sm(6), and one Ti(1) atom to form OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids, corners with two equivalent O(5)Sm3Ti tetrahedra,  an edgeedge with one Se(11)Sm5 square pyramid, and edges with two equivalent O(6)Sm3Ti tetrahedra. In the sixth O site, O(6) is bonded to one Sm(6), two equivalent Sm(5), and one Ti(2) atom to form OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids, corners with two equivalent O(6)Sm3Ti tetrahedra,  a cornercorner with one Se(10)Sm4Ti trigonal bipyramid, and edges with two equivalent O(5)Sm3Ti tetrahedra.
Sm7Ti4(Se2O)6 crystallizes in the monoclinic Cm space group. There are seven inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to one Se(5), two equivalent Se(12), two equivalent Se(2), one O(4), and two equivalent O(2) atoms. The Sm(1)-Se(5) bond length is 3.06 Å. Both Sm(1)-Se(12) bond lengths are 2.95 Å. Both Sm(1)-Se(2) bond lengths are 3.13 Å. The Sm(1)-O(4) bond length is 2.51 Å. Both Sm(1)-O(2) bond lengths are 2.38 Å. In the second Sm site, Sm(2) is bonded in a 3-coordinate geometry to one Se(6), two equivalent Se(1), two equivalent Se(11), one O(3), and two equivalent O(1) atoms. The Sm(2)-Se(6) bond length is 3.05 Å. Both Sm(2)-Se(1) bond lengths are 3.14 Å. Both Sm(2)-Se(11) bond lengths are 3.05 Å. The Sm(2)-O(3) bond length is 2.39 Å. Both Sm(2)-O(1) bond lengths are 2.31 Å. In the third Sm site, Sm(3) is bonded in a 9-coordinate geometry to one Se(2), one Se(4), two equivalent Se(5), two equivalent Se(9), one O(1), and two equivalent O(3) atoms. The Sm(3)-Se(2) bond length is 3.11 Å. The Sm(3)-Se(4) bond length is 3.17 Å. Both Sm(3)-Se(5) bond lengths are 3.19 Å. Both Sm(3)-Se(9) bond lengths are 2.98 Å. The Sm(3)-O(1) bond length is 2.59 Å. Both Sm(3)-O(3) bond lengths are 2.45 Å. In the fourth Sm site, Sm(4) is bonded in a 3-coordinate geometry to one Se(1), one Se(3), two equivalent Se(10), two equivalent Se(6), one O(2), and two equivalent O(4) atoms. The Sm(4)-Se(1) bond length is 3.16 Å. The Sm(4)-Se(3) bond length is 3.24 Å. Both Sm(4)-Se(10) bond lengths are 3.15 Å. Both Sm(4)-Se(6) bond lengths are 3.18 Å. The Sm(4)-O(2) bond length is 2.41 Å. Both Sm(4)-O(4) bond lengths are 2.35 Å. In the fifth Sm site, Sm(5) is bonded in a 3-coordinate geometry to one Se(8), two equivalent Se(12), two equivalent Se(4), one O(5), and two equivalent O(6) atoms. The Sm(5)-Se(8) bond length is 3.35 Å. Both Sm(5)-Se(12) bond lengths are 2.93 Å. Both Sm(5)-Se(4) bond lengths are 3.06 Å. The Sm(5)-O(5) bond length is 2.47 Å. Both Sm(5)-O(6) bond lengths are 2.42 Å. In the sixth Sm site, Sm(6) is bonded in a 3-coordinate geometry to one Se(7), two equivalent Se(11), two equivalent Se(3), one O(6), and two equivalent O(5) atoms. The Sm(6)-Se(7) bond length is 3.24 Å. Both Sm(6)-Se(11) bond lengths are 3.02 Å. Both Sm(6)-Se(3) bond lengths are 3.15 Å. The Sm(6)-O(6) bond length is 2.42 Å. Both Sm(6)-O(5) bond lengths are 2.35 Å. In the seventh Sm site, Sm(7) is bonded in a 7-coordinate geometry to one Se(1), one Se(11), one Se(8), two equivalent Se(10), and two equivalent Se(7) atoms. The Sm(7)-Se(1) bond length is 3.16 Å. The Sm(7)-Se(11) bond length is 2.92 Å. The Sm(7)-Se(8) bond length is 3.17 Å. Both Sm(7)-Se(10) bond lengths are 2.89 Å. Both Sm(7)-Se(7) bond lengths are 2.96 Å. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one Se(9), two equivalent Se(4), two equivalent Se(7), and one O(5) atom to form distorted edge-sharing TiSe5O octahedra. The Ti(1)-Se(9) bond length is 2.44 Å. Both Ti(1)-Se(4) bond lengths are 2.66 Å. Both Ti(1)-Se(7) bond lengths are 2.65 Å. The Ti(1)-O(5) bond length is 1.97 Å. In the second Ti site, Ti(2) is bonded in a distorted single-bond geometry to one Se(10), two equivalent Se(3), two equivalent Se(8), and one O(6) atom. The Ti(2)-Se(10) bond length is 2.64 Å. Both Ti(2)-Se(3) bond lengths are 2.72 Å. Both Ti(2)-Se(8) bond lengths are 2.56 Å. The Ti(2)-O(6) bond length is 1.85 Å. In the third Ti site, Ti(3) is bonded in a distorted linear geometry to two equivalent Se(5), two equivalent Se(6), one O(1), and one O(2) atom. Both Ti(3)-Se(5) bond lengths are 2.66 Å. Both Ti(3)-Se(6) bond lengths are 2.68 Å. The Ti(3)-O(1) bond length is 1.92 Å. The Ti(3)-O(2) bond length is 1.92 Å. In the fourth Ti site, Ti(4) is bonded in a distorted linear geometry to two equivalent Se(1), two equivalent Se(2), one O(3), and one O(4) atom. Both Ti(4)-Se(1) bond lengths are 2.68 Å. Both Ti(4)-Se(2) bond lengths are 2.61 Å. The Ti(4)-O(3) bond length is 1.92 Å. The Ti(4)-O(4) bond length is 1.96 Å. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one Sm(4), one Sm(7), two equivalent Sm(2), and two equivalent Ti(4) atoms. In the second Se site, Se(2) is bonded in a distorted pentagonal planar geometry to one Sm(3), two equivalent Sm(1), and two equivalent Ti(4) atoms. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one Sm(4), two equivalent Sm(6), and two equivalent Ti(2) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to one Sm(3), two equivalent Sm(5), and two equivalent Ti(1) atoms. In the fifth Se site, Se(5) is bonded in a distorted pentagonal planar geometry to one Sm(1), two equivalent Sm(3), and two equivalent Ti(3) atoms. In the sixth Se site, Se(6) is bonded in a distorted pentagonal planar geometry to one Sm(2), two equivalent Sm(4), and two equivalent Ti(3) atoms. In the seventh Se site, Se(7) is bonded in a 5-coordinate geometry to one Sm(6), two equivalent Sm(7), and two equivalent Ti(1) atoms. In the eighth Se site, Se(8) is bonded in a 4-coordinate geometry to one Sm(5), one Sm(7), and two equivalent Ti(2) atoms. In the ninth Se site, Se(9) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Sm(3) and one Ti(1) atom. In the tenth Se site, Se(10) is bonded to two equivalent Sm(4), two equivalent Sm(7), and one Ti(2) atom to form distorted SeSm4Ti trigonal bipyramids that share corners with two equivalent Se(11)Sm5 square pyramids,  a cornercorner with one O(6)Sm3Ti tetrahedra, corners with two equivalent O(2)Sm3Ti tetrahedra, corners with two equivalent O(4)Sm3Ti tetrahedra,  an edgeedge with one O(4)Sm3Ti tetrahedra, and edges with two equivalent Se(10)Sm4Ti trigonal bipyramids. In the eleventh Se site, Se(11) is bonded to one Sm(7), two equivalent Sm(2), and two equivalent Sm(6) atoms to form distorted SeSm5 square pyramids that share corners with two equivalent O(1)Sm3Ti tetrahedra, corners with two equivalent O(3)Sm3Ti tetrahedra, corners with two equivalent O(5)Sm3Ti tetrahedra, corners with two equivalent O(6)Sm3Ti tetrahedra, corners with two equivalent Se(10)Sm4Ti trigonal bipyramids, edges with two equivalent Se(11)Sm5 square pyramids,  an edgeedge with one O(1)Sm3Ti tetrahedra, and  an edgeedge with one O(5)Sm3Ti tetrahedra. In the twelfth Se site, Se(12) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sm(1) and two equivalent Sm(5) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Sm(3), two equivalent Sm(2), and one Ti(3) atom to form distorted OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids,  a cornercorner with one O(2)Sm3Ti tetrahedra, corners with two equivalent O(1)Sm3Ti tetrahedra,  an edgeedge with one Se(11)Sm5 square pyramid, and edges with two equivalent O(3)Sm3Ti tetrahedra. In the second O site, O(2) is bonded to one Sm(4), two equivalent Sm(1), and one Ti(3) atom to form OSm3Ti tetrahedra that share  a cornercorner with one O(1)Sm3Ti tetrahedra, corners with two equivalent O(2)Sm3Ti tetrahedra, corners with two equivalent Se(10)Sm4Ti trigonal bipyramids, and edges with two equivalent O(4)Sm3Ti tetrahedra. In the third O site, O(3) is bonded to one Sm(2), two equivalent Sm(3), and one Ti(4) atom to form OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids,  a cornercorner with one O(4)Sm3Ti tetrahedra, corners with two equivalent O(3)Sm3Ti tetrahedra, and edges with two equivalent O(1)Sm3Ti tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), two equivalent Sm(4), and one Ti(4) atom to form distorted OSm3Ti tetrahedra that share  a cornercorner with one O(3)Sm3Ti tetrahedra, corners with two equivalent O(4)Sm3Ti tetrahedra, corners with two equivalent Se(10)Sm4Ti trigonal bipyramids, edges with two equivalent O(2)Sm3Ti tetrahedra, and  an edgeedge with one Se(10)Sm4Ti trigonal bipyramid. In the fifth O site, O(5) is bonded to one Sm(5), two equivalent Sm(6), and one Ti(1) atom to form OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids, corners with two equivalent O(5)Sm3Ti tetrahedra,  an edgeedge with one Se(11)Sm5 square pyramid, and edges with two equivalent O(6)Sm3Ti tetrahedra. In the sixth O site, O(6) is bonded to one Sm(6), two equivalent Sm(5), and one Ti(2) atom to form OSm3Ti tetrahedra that share corners with two equivalent Se(11)Sm5 square pyramids, corners with two equivalent O(6)Sm3Ti tetrahedra,  a cornercorner with one Se(10)Sm4Ti trigonal bipyramid, and edges with two equivalent O(5)Sm3Ti tetrahedra.