MgWTl6O12 crystallizes in the trigonal R3 space group. Mg(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Tl(1)O6 octahedra, corners with three equivalent Tl(2)O5 trigonal bipyramids, edges with three equivalent Tl(2)O5 trigonal bipyramids, and  a faceface with one W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-46°. W(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted WO6 octahedra that share corners with three equivalent Tl(1)O6 octahedra, corners with three equivalent Tl(2)O5 trigonal bipyramids, edges with three equivalent Tl(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 41°. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted TlO6 octahedra that share  a cornercorner with one W(1)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Tl(1)O6 octahedra, corners with three equivalent Tl(2)O5 trigonal bipyramids,  an edgeedge with one W(1)O6 octahedra, and edges with two equivalent Tl(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-69°. In the second Tl site, Tl(2) is bonded to one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted TlO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one W(1)O6 octahedra, corners with three equivalent Tl(1)O6 octahedra, corners with four equivalent Tl(2)O5 trigonal bipyramids,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Tl(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-74°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one W(1) and two equivalent Tl(1) atoms. In the second O site, O(2) is bonded to one Mg(1), one W(1), one Tl(1), and one Tl(2) atom to form distorted OMgTl2W trigonal pyramids that share corners with two equivalent O(4)Tl4 tetrahedra,  an edgeedge with one O(4)Tl4 tetrahedra, and edges with two equivalent O(2)MgTl2W trigonal pyramids. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Mg(1), one Tl(1), and two equivalent Tl(2) atoms. In the fourth O site, O(4) is bonded to two equivalent Tl(1) and two equivalent Tl(2) atoms to form OTl4 tetrahedra that share corners with four equivalent O(4)Tl4 tetrahedra, corners with two equivalent O(2)MgTl2W trigonal pyramids, and  an edgeedge with one O(2)MgTl2W trigonal pyramid.
MgWTl6O12 crystallizes in the trigonal R3 space group. Mg(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Tl(1)O6 octahedra, corners with three equivalent Tl(2)O5 trigonal bipyramids, edges with three equivalent Tl(2)O5 trigonal bipyramids, and  a faceface with one W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-46°. All Mg(1)-O(2) bond lengths are 2.16 Å. All Mg(1)-O(3) bond lengths are 2.21 Å. W(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted WO6 octahedra that share corners with three equivalent Tl(1)O6 octahedra, corners with three equivalent Tl(2)O5 trigonal bipyramids, edges with three equivalent Tl(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 41°. All W(1)-O(1) bond lengths are 1.88 Å. All W(1)-O(2) bond lengths are 2.07 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted TlO6 octahedra that share  a cornercorner with one W(1)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Tl(1)O6 octahedra, corners with three equivalent Tl(2)O5 trigonal bipyramids,  an edgeedge with one W(1)O6 octahedra, and edges with two equivalent Tl(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-69°. The Tl(1)-O(2) bond length is 2.52 Å. The Tl(1)-O(3) bond length is 2.24 Å. There is one shorter (2.39 Å) and one longer (2.46 Å) Tl(1)-O(1) bond length. There is one shorter (2.21 Å) and one longer (2.41 Å) Tl(1)-O(4) bond length. In the second Tl site, Tl(2) is bonded to one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted TlO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one W(1)O6 octahedra, corners with three equivalent Tl(1)O6 octahedra, corners with four equivalent Tl(2)O5 trigonal bipyramids,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Tl(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-74°. The Tl(2)-O(2) bond length is 2.30 Å. There is one shorter (2.26 Å) and one longer (2.39 Å) Tl(2)-O(3) bond length. There is one shorter (2.29 Å) and one longer (2.37 Å) Tl(2)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one W(1) and two equivalent Tl(1) atoms. In the second O site, O(2) is bonded to one Mg(1), one W(1), one Tl(1), and one Tl(2) atom to form distorted OMgTl2W trigonal pyramids that share corners with two equivalent O(4)Tl4 tetrahedra,  an edgeedge with one O(4)Tl4 tetrahedra, and edges with two equivalent O(2)MgTl2W trigonal pyramids. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Mg(1), one Tl(1), and two equivalent Tl(2) atoms. In the fourth O site, O(4) is bonded to two equivalent Tl(1) and two equivalent Tl(2) atoms to form OTl4 tetrahedra that share corners with four equivalent O(4)Tl4 tetrahedra, corners with two equivalent O(2)MgTl2W trigonal pyramids, and  an edgeedge with one O(2)MgTl2W trigonal pyramid.