Sr3Tl2O6 crystallizes in the orthorhombic Pbam space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(4), two equivalent O(1), two equivalent O(5), and two equivalent O(7) atoms to form distorted SrO7 pentagonal bipyramids that share corners with two equivalent Sr(2)O6 octahedra, corners with two equivalent Tl(1)O6 octahedra, corners with four equivalent Sr(3)O6 octahedra,  a cornercorner with one Sr(1)O7 pentagonal bipyramid,  an edgeedge with one Sr(2)O6 octahedra, edges with two equivalent Sr(3)O6 octahedra, edges with four equivalent Tl(2)O6 octahedra, and faces with two equivalent Sr(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 23-71°. In the second Sr site, Sr(2) is bonded to one O(2), one O(3), two equivalent O(5), and two equivalent O(6) atoms to form SrO6 octahedra that share corners with two equivalent Sr(2)O6 octahedra, corners with two equivalent Sr(3)O6 octahedra, corners with two equivalent Sr(1)O7 pentagonal bipyramids, edges with two equivalent Tl(2)O6 octahedra, edges with three equivalent Sr(2)O6 octahedra, edges with four equivalent Tl(1)O6 octahedra, and  an edgeedge with one Sr(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 0-74°. In the third Sr site, Sr(3) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(7) atoms to form SrO6 octahedra that share corners with two equivalent Sr(2)O6 octahedra, corners with two equivalent Tl(1)O6 octahedra, corners with four equivalent Sr(1)O7 pentagonal bipyramids, edges with two equivalent Sr(3)O6 octahedra, edges with two equivalent Tl(1)O6 octahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with two equivalent Sr(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 9-74°. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(3) atoms to form distorted TlO6 octahedra that share  a cornercorner with one Tl(1)O6 octahedra, corners with two equivalent Sr(3)O6 octahedra, corners with two equivalent Tl(2)O6 octahedra, corners with two equivalent Sr(1)O7 pentagonal bipyramids,  an edgeedge with one Tl(2)O6 octahedra, edges with two equivalent Sr(3)O6 octahedra, edges with two equivalent Tl(1)O6 octahedra, and edges with four equivalent Sr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the second Tl site, Tl(2) is bonded to one O(5), one O(7), two equivalent O(3), and two equivalent O(4) atoms to form distorted TlO6 octahedra that share corners with two equivalent Tl(1)O6 octahedra, corners with two equivalent Tl(2)O6 octahedra,  an edgeedge with one Tl(1)O6 octahedra, edges with two equivalent Sr(2)O6 octahedra, edges with two equivalent Sr(3)O6 octahedra, edges with three equivalent Tl(2)O6 octahedra, and edges with four equivalent Sr(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 0-7°. There are seven inequivalent O sites. In the first O site, O(4) is bonded to two equivalent Sr(1) and four equivalent Tl(2) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with four equivalent O(1)Sr4Tl trigonal bipyramids, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(4)Sr2Tl4 octahedra, edges with four equivalent O(5)Sr4Tl square pyramids, and edges with four equivalent O(7)Sr4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. In the second O site, O(5) is bonded to two equivalent Sr(1), two equivalent Sr(2), and one Tl(2) atom to form distorted OSr4Tl square pyramids that share corners with two equivalent O(6)Sr4Tl2 octahedra, corners with two equivalent O(2)Sr2Tl2 tetrahedra, corners with two equivalent O(1)Sr4Tl trigonal bipyramids, corners with three equivalent O(7)Sr4Tl trigonal bipyramids,  an edgeedge with one O(6)Sr4Tl2 octahedra, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(4)Sr2Tl4 octahedra, edges with two equivalent O(5)Sr4Tl square pyramids,  an edgeedge with one O(1)Sr4Tl trigonal bipyramid, and  an edgeedge with one O(7)Sr4Tl trigonal bipyramid. The corner-sharing octahedral tilt angles are 8°. In the third O site, O(6) is bonded to four equivalent Sr(2) and two equivalent Tl(1) atoms to form OSr4Tl2 octahedra that share corners with four equivalent O(5)Sr4Tl square pyramids, corners with two equivalent O(1)Sr4Tl trigonal bipyramids, edges with two equivalent O(6)Sr4Tl2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(5)Sr4Tl square pyramids, and edges with four equivalent O(2)Sr2Tl2 tetrahedra. In the fourth O site, O(7) is bonded to two equivalent Sr(1), two equivalent Sr(3), and one Tl(2) atom to form distorted OSr4Tl trigonal bipyramids that share corners with three equivalent O(5)Sr4Tl square pyramids, corners with two equivalent O(2)Sr2Tl2 tetrahedra, corners with four equivalent O(1)Sr4Tl trigonal bipyramids, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(4)Sr2Tl4 octahedra,  an edgeedge with one O(5)Sr4Tl square pyramid, edges with two equivalent O(1)Sr4Tl trigonal bipyramids, and edges with two equivalent O(7)Sr4Tl trigonal bipyramids. In the fifth O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(3), and one Tl(1) atom to form distorted OSr4Tl trigonal bipyramids that share  a cornercorner with one O(6)Sr4Tl2 octahedra, corners with two equivalent O(4)Sr2Tl4 octahedra, corners with two equivalent O(5)Sr4Tl square pyramids, corners with four equivalent O(2)Sr2Tl2 tetrahedra, corners with four equivalent O(7)Sr4Tl trigonal bipyramids, edges with two equivalent O(3)Sr2Tl4 octahedra,  an edgeedge with one O(5)Sr4Tl square pyramid, edges with two equivalent O(1)Sr4Tl trigonal bipyramids, and edges with two equivalent O(7)Sr4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles range from 7-43°. In the sixth O site, O(2) is bonded to one Sr(2), one Sr(3), and two equivalent Tl(1) atoms to form OSr2Tl2 tetrahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with two equivalent O(5)Sr4Tl square pyramids, corners with two equivalent O(2)Sr2Tl2 tetrahedra, corners with two equivalent O(7)Sr4Tl trigonal bipyramids, corners with four equivalent O(1)Sr4Tl trigonal bipyramids,  an edgeedge with one O(3)Sr2Tl4 octahedra, and edges with two equivalent O(6)Sr4Tl2 octahedra. The corner-sharing octahedral tilt angles range from 8-13°. In the seventh O site, O(3) is bonded to one Sr(2), one Sr(3), two equivalent Tl(1), and two equivalent Tl(2) atoms to form OSr2Tl4 octahedra that share corners with two equivalent O(4)Sr2Tl4 octahedra, corners with four equivalent O(2)Sr2Tl2 tetrahedra,  an edgeedge with one O(4)Sr2Tl4 octahedra, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(6)Sr4Tl2 octahedra, edges with two equivalent O(5)Sr4Tl square pyramids,  an edgeedge with one O(2)Sr2Tl2 tetrahedra, edges with two equivalent O(1)Sr4Tl trigonal bipyramids, and edges with two equivalent O(7)Sr4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°.
Sr3Tl2O6 crystallizes in the orthorhombic Pbam space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(4), two equivalent O(1), two equivalent O(5), and two equivalent O(7) atoms to form distorted SrO7 pentagonal bipyramids that share corners with two equivalent Sr(2)O6 octahedra, corners with two equivalent Tl(1)O6 octahedra, corners with four equivalent Sr(3)O6 octahedra,  a cornercorner with one Sr(1)O7 pentagonal bipyramid,  an edgeedge with one Sr(2)O6 octahedra, edges with two equivalent Sr(3)O6 octahedra, edges with four equivalent Tl(2)O6 octahedra, and faces with two equivalent Sr(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 23-71°. The Sr(1)-O(4) bond length is 2.77 Å. Both Sr(1)-O(1) bond lengths are 2.61 Å. Both Sr(1)-O(5) bond lengths are 2.65 Å. Both Sr(1)-O(7) bond lengths are 2.59 Å. In the second Sr site, Sr(2) is bonded to one O(2), one O(3), two equivalent O(5), and two equivalent O(6) atoms to form SrO6 octahedra that share corners with two equivalent Sr(2)O6 octahedra, corners with two equivalent Sr(3)O6 octahedra, corners with two equivalent Sr(1)O7 pentagonal bipyramids, edges with two equivalent Tl(2)O6 octahedra, edges with three equivalent Sr(2)O6 octahedra, edges with four equivalent Tl(1)O6 octahedra, and  an edgeedge with one Sr(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 0-74°. The Sr(2)-O(2) bond length is 2.56 Å. The Sr(2)-O(3) bond length is 2.56 Å. Both Sr(2)-O(5) bond lengths are 2.59 Å. Both Sr(2)-O(6) bond lengths are 2.48 Å. In the third Sr site, Sr(3) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(7) atoms to form SrO6 octahedra that share corners with two equivalent Sr(2)O6 octahedra, corners with two equivalent Tl(1)O6 octahedra, corners with four equivalent Sr(1)O7 pentagonal bipyramids, edges with two equivalent Sr(3)O6 octahedra, edges with two equivalent Tl(1)O6 octahedra, edges with two equivalent Tl(2)O6 octahedra, and edges with two equivalent Sr(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 9-74°. The Sr(3)-O(2) bond length is 2.53 Å. The Sr(3)-O(3) bond length is 2.60 Å. Both Sr(3)-O(1) bond lengths are 2.51 Å. Both Sr(3)-O(7) bond lengths are 2.55 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(3) atoms to form distorted TlO6 octahedra that share  a cornercorner with one Tl(1)O6 octahedra, corners with two equivalent Sr(3)O6 octahedra, corners with two equivalent Tl(2)O6 octahedra, corners with two equivalent Sr(1)O7 pentagonal bipyramids,  an edgeedge with one Tl(2)O6 octahedra, edges with two equivalent Sr(3)O6 octahedra, edges with two equivalent Tl(1)O6 octahedra, and edges with four equivalent Sr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. The Tl(1)-O(1) bond length is 2.27 Å. The Tl(1)-O(6) bond length is 2.77 Å. Both Tl(1)-O(2) bond lengths are 2.30 Å. Both Tl(1)-O(3) bond lengths are 2.46 Å. In the second Tl site, Tl(2) is bonded to one O(5), one O(7), two equivalent O(3), and two equivalent O(4) atoms to form distorted TlO6 octahedra that share corners with two equivalent Tl(1)O6 octahedra, corners with two equivalent Tl(2)O6 octahedra,  an edgeedge with one Tl(1)O6 octahedra, edges with two equivalent Sr(2)O6 octahedra, edges with two equivalent Sr(3)O6 octahedra, edges with three equivalent Tl(2)O6 octahedra, and edges with four equivalent Sr(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 0-7°. The Tl(2)-O(5) bond length is 2.10 Å. The Tl(2)-O(7) bond length is 2.10 Å. Both Tl(2)-O(3) bond lengths are 2.73 Å. Both Tl(2)-O(4) bond lengths are 2.48 Å. There are seven inequivalent O sites. In the first O site, O(4) is bonded to two equivalent Sr(1) and four equivalent Tl(2) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with four equivalent O(1)Sr4Tl trigonal bipyramids, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(4)Sr2Tl4 octahedra, edges with four equivalent O(5)Sr4Tl square pyramids, and edges with four equivalent O(7)Sr4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. In the second O site, O(5) is bonded to two equivalent Sr(1), two equivalent Sr(2), and one Tl(2) atom to form distorted OSr4Tl square pyramids that share corners with two equivalent O(6)Sr4Tl2 octahedra, corners with two equivalent O(2)Sr2Tl2 tetrahedra, corners with two equivalent O(1)Sr4Tl trigonal bipyramids, corners with three equivalent O(7)Sr4Tl trigonal bipyramids,  an edgeedge with one O(6)Sr4Tl2 octahedra, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(4)Sr2Tl4 octahedra, edges with two equivalent O(5)Sr4Tl square pyramids,  an edgeedge with one O(1)Sr4Tl trigonal bipyramid, and  an edgeedge with one O(7)Sr4Tl trigonal bipyramid. The corner-sharing octahedral tilt angles are 8°. In the third O site, O(6) is bonded to four equivalent Sr(2) and two equivalent Tl(1) atoms to form OSr4Tl2 octahedra that share corners with four equivalent O(5)Sr4Tl square pyramids, corners with two equivalent O(1)Sr4Tl trigonal bipyramids, edges with two equivalent O(6)Sr4Tl2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(5)Sr4Tl square pyramids, and edges with four equivalent O(2)Sr2Tl2 tetrahedra. In the fourth O site, O(7) is bonded to two equivalent Sr(1), two equivalent Sr(3), and one Tl(2) atom to form distorted OSr4Tl trigonal bipyramids that share corners with three equivalent O(5)Sr4Tl square pyramids, corners with two equivalent O(2)Sr2Tl2 tetrahedra, corners with four equivalent O(1)Sr4Tl trigonal bipyramids, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(4)Sr2Tl4 octahedra,  an edgeedge with one O(5)Sr4Tl square pyramid, edges with two equivalent O(1)Sr4Tl trigonal bipyramids, and edges with two equivalent O(7)Sr4Tl trigonal bipyramids. In the fifth O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(3), and one Tl(1) atom to form distorted OSr4Tl trigonal bipyramids that share  a cornercorner with one O(6)Sr4Tl2 octahedra, corners with two equivalent O(4)Sr2Tl4 octahedra, corners with two equivalent O(5)Sr4Tl square pyramids, corners with four equivalent O(2)Sr2Tl2 tetrahedra, corners with four equivalent O(7)Sr4Tl trigonal bipyramids, edges with two equivalent O(3)Sr2Tl4 octahedra,  an edgeedge with one O(5)Sr4Tl square pyramid, edges with two equivalent O(1)Sr4Tl trigonal bipyramids, and edges with two equivalent O(7)Sr4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles range from 7-43°. In the sixth O site, O(2) is bonded to one Sr(2), one Sr(3), and two equivalent Tl(1) atoms to form OSr2Tl2 tetrahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with two equivalent O(5)Sr4Tl square pyramids, corners with two equivalent O(2)Sr2Tl2 tetrahedra, corners with two equivalent O(7)Sr4Tl trigonal bipyramids, corners with four equivalent O(1)Sr4Tl trigonal bipyramids,  an edgeedge with one O(3)Sr2Tl4 octahedra, and edges with two equivalent O(6)Sr4Tl2 octahedra. The corner-sharing octahedral tilt angles range from 8-13°. In the seventh O site, O(3) is bonded to one Sr(2), one Sr(3), two equivalent Tl(1), and two equivalent Tl(2) atoms to form OSr2Tl4 octahedra that share corners with two equivalent O(4)Sr2Tl4 octahedra, corners with four equivalent O(2)Sr2Tl2 tetrahedra,  an edgeedge with one O(4)Sr2Tl4 octahedra, edges with two equivalent O(3)Sr2Tl4 octahedra, edges with two equivalent O(6)Sr4Tl2 octahedra, edges with two equivalent O(5)Sr4Tl square pyramids,  an edgeedge with one O(2)Sr2Tl2 tetrahedra, edges with two equivalent O(1)Sr4Tl trigonal bipyramids, and edges with two equivalent O(7)Sr4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°.