Hg2CdSO6 crystallizes in the triclinic P-1 space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a linear geometry to one O(2) and one O(5) atom. In the second Hg site, Hg(2) is bonded in a linear geometry to one O(2) and one O(5) atom. Cd(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form CdO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and  an edgeedge with one Cd(1)O6 octahedra. S(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-49°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cd(1) and one S(1) atom. In the second O site, O(2) is bonded to one Hg(1), one Hg(2), and two equivalent Cd(1) atoms to form edge-sharing OCd2Hg2 tetrahedra. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Cd(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cd(1) and one S(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Hg(1), one Hg(2), and one Cd(1) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to one S(1) atom.
Hg2CdSO6 crystallizes in the triclinic P-1 space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a linear geometry to one O(2) and one O(5) atom. The Hg(1)-O(2) bond length is 2.07 Å. The Hg(1)-O(5) bond length is 2.04 Å. In the second Hg site, Hg(2) is bonded in a linear geometry to one O(2) and one O(5) atom. The Hg(2)-O(2) bond length is 2.08 Å. The Hg(2)-O(5) bond length is 2.05 Å. Cd(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form CdO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and  an edgeedge with one Cd(1)O6 octahedra. The Cd(1)-O(1) bond length is 2.30 Å. The Cd(1)-O(3) bond length is 2.29 Å. The Cd(1)-O(4) bond length is 2.33 Å. The Cd(1)-O(5) bond length is 2.30 Å. There is one shorter (2.34 Å) and one longer (2.49 Å) Cd(1)-O(2) bond length. S(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-49°. The S(1)-O(1) bond length is 1.50 Å. The S(1)-O(3) bond length is 1.50 Å. The S(1)-O(4) bond length is 1.50 Å. The S(1)-O(6) bond length is 1.48 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cd(1) and one S(1) atom. In the second O site, O(2) is bonded to one Hg(1), one Hg(2), and two equivalent Cd(1) atoms to form edge-sharing OCd2Hg2 tetrahedra. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Cd(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cd(1) and one S(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Hg(1), one Hg(2), and one Cd(1) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to one S(1) atom.