MgHg2(SbO3)4 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(4)O6 octahedra, edges with two equivalent Hg(1)O6 octahedra, and edges with two equivalent Sb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-61°. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form distorted HgO6 octahedra that share corners with four equivalent Sb(3)O6 octahedra, corners with four equivalent Sb(4)O6 octahedra,  an edgeedge with one Sb(1)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, and edges with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-61°. In the second Hg site, Hg(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form HgO6 octahedra that share corners with four equivalent Sb(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra,  an edgeedge with one Sb(3)O6 octahedra, and  an edgeedge with one Sb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-56°. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with four equivalent Hg(2)O6 octahedra, corners with four equivalent Sb(3)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Hg(1)O6 octahedra, and  an edgeedge with one Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-56°. In the second Sb site, Sb(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form SbO6 octahedra that share corners with four equivalent Hg(2)O6 octahedra, corners with four equivalent Sb(4)O6 octahedra,  an edgeedge with one Hg(1)O6 octahedra, and  an edgeedge with one Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-55°. In the third Sb site, Sb(3) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms to form SbO6 octahedra that share corners with four equivalent Hg(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra,  an edgeedge with one Hg(2)O6 octahedra,  an edgeedge with one Sb(4)O6 octahedra, and edges with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-52°. In the fourth Sb site, Sb(4) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form SbO6 octahedra that share corners with four equivalent Hg(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Hg(2)O6 octahedra, and  an edgeedge with one Sb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-61°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Hg(2), one Sb(1), and one Sb(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Hg(1), one Sb(2), and one Sb(4) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one Hg(1), one Sb(1), and one Sb(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Hg(2), one Sb(1), and one Sb(3) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Hg(2), one Sb(2), and one Sb(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Mg(1), one Hg(1), one Sb(3), and one Sb(4) atom.
MgHg2(SbO3)4 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(4)O6 octahedra, edges with two equivalent Hg(1)O6 octahedra, and edges with two equivalent Sb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-61°. Both Mg(1)-O(3) bond lengths are 2.00 Å. Both Mg(1)-O(6) bond lengths are 1.97 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form distorted HgO6 octahedra that share corners with four equivalent Sb(3)O6 octahedra, corners with four equivalent Sb(4)O6 octahedra,  an edgeedge with one Sb(1)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, and edges with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-61°. Both Hg(1)-O(2) bond lengths are 2.30 Å. Both Hg(1)-O(3) bond lengths are 2.52 Å. Both Hg(1)-O(6) bond lengths are 2.42 Å. In the second Hg site, Hg(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form HgO6 octahedra that share corners with four equivalent Sb(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra,  an edgeedge with one Sb(3)O6 octahedra, and  an edgeedge with one Sb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-56°. Both Hg(2)-O(1) bond lengths are 2.40 Å. Both Hg(2)-O(4) bond lengths are 2.46 Å. Both Hg(2)-O(5) bond lengths are 2.38 Å. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with four equivalent Hg(2)O6 octahedra, corners with four equivalent Sb(3)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Hg(1)O6 octahedra, and  an edgeedge with one Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-56°. Both Sb(1)-O(1) bond lengths are 2.04 Å. Both Sb(1)-O(3) bond lengths are 2.16 Å. Both Sb(1)-O(4) bond lengths are 2.08 Å. In the second Sb site, Sb(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form SbO6 octahedra that share corners with four equivalent Hg(2)O6 octahedra, corners with four equivalent Sb(4)O6 octahedra,  an edgeedge with one Hg(1)O6 octahedra, and  an edgeedge with one Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-55°. Both Sb(2)-O(1) bond lengths are 2.06 Å. Both Sb(2)-O(2) bond lengths are 2.13 Å. Both Sb(2)-O(5) bond lengths are 2.10 Å. In the third Sb site, Sb(3) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms to form SbO6 octahedra that share corners with four equivalent Hg(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra,  an edgeedge with one Hg(2)O6 octahedra,  an edgeedge with one Sb(4)O6 octahedra, and edges with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-52°. Both Sb(3)-O(3) bond lengths are 2.13 Å. Both Sb(3)-O(4) bond lengths are 2.04 Å. Both Sb(3)-O(6) bond lengths are 2.16 Å. In the fourth Sb site, Sb(4) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form SbO6 octahedra that share corners with four equivalent Hg(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Hg(2)O6 octahedra, and  an edgeedge with one Sb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-61°. Both Sb(4)-O(2) bond lengths are 2.11 Å. Both Sb(4)-O(5) bond lengths are 2.06 Å. Both Sb(4)-O(6) bond lengths are 2.18 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Hg(2), one Sb(1), and one Sb(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Hg(1), one Sb(2), and one Sb(4) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one Hg(1), one Sb(1), and one Sb(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Hg(2), one Sb(1), and one Sb(3) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Hg(2), one Sb(2), and one Sb(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Mg(1), one Hg(1), one Sb(3), and one Sb(4) atom.