CsHgCl3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), two equivalent Cl(4), two equivalent Cl(5), and two equivalent Cl(6) atoms to form CsCl12 cuboctahedra that share corners with four equivalent Cs(3)Cl12 cuboctahedra, corners with eight equivalent Cs(2)Cl12 cuboctahedra, edges with two equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(3)Cl12 cuboctahedra, faces with four equivalent Cs(2)Cl12 cuboctahedra, faces with two equivalent Hg(2)Cl6 octahedra, and faces with two equivalent Hg(3)Cl5 square pyramids. In the second Cs site, Cs(2) is bonded to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), two equivalent Cl(4), two equivalent Cl(5), and two equivalent Cl(6) atoms to form CsCl12 cuboctahedra that share corners with four equivalent Cs(1)Cl12 cuboctahedra, corners with four equivalent Cs(2)Cl12 cuboctahedra, corners with four equivalent Cs(3)Cl12 cuboctahedra, edges with two equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(1)Cl12 cuboctahedra, faces with two equivalent Cs(2)Cl12 cuboctahedra, faces with two equivalent Cs(3)Cl12 cuboctahedra, faces with two equivalent Hg(2)Cl6 octahedra, and faces with two equivalent Hg(3)Cl5 square pyramids. In the third Cs site, Cs(3) is bonded to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), two equivalent Cl(4), two equivalent Cl(5), and two equivalent Cl(6) atoms to form CsCl12 cuboctahedra that share corners with four equivalent Cs(1)Cl12 cuboctahedra, corners with eight equivalent Cs(2)Cl12 cuboctahedra, edges with two equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(1)Cl12 cuboctahedra, faces with four equivalent Cs(2)Cl12 cuboctahedra, faces with two equivalent Hg(2)Cl6 octahedra, and faces with two equivalent Hg(3)Cl5 square pyramids. There are three inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a distorted square co-planar geometry to two equivalent Cl(2) and two equivalent Cl(5) atoms. In the second Hg site, Hg(2) is bonded to two equivalent Cl(1), two equivalent Cl(3), and two equivalent Cl(4) atoms to form distorted HgCl6 octahedra that share corners with four equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(1)Cl12 cuboctahedra, faces with two equivalent Cs(3)Cl12 cuboctahedra, and faces with four equivalent Cs(2)Cl12 cuboctahedra. In the third Hg site, Hg(3) is bonded to one Cl(3), one Cl(4), one Cl(5), and two equivalent Cl(6) atoms to form HgCl5 square pyramids that share corners with two equivalent Hg(2)Cl6 octahedra, corners with two equivalent Hg(3)Cl5 square pyramids,  an edgeedge with one Cs(1)Cl12 cuboctahedra,  an edgeedge with one Cs(3)Cl12 cuboctahedra, edges with two equivalent Cs(2)Cl12 cuboctahedra,  a faceface with one Cs(1)Cl12 cuboctahedra,  a faceface with one Cs(3)Cl12 cuboctahedra, and faces with two equivalent Cs(2)Cl12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-5°. There are six inequivalent Cl sites. In the first Cl site, Cl(5) is bonded to one Cs(1), one Cs(3), two equivalent Cs(2), one Hg(1), and one Hg(3) atom to form a mixture of distorted face, corner, and edge-sharing ClCs4Hg2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second Cl site, Cl(6) is bonded to one Cs(1), one Cs(3), two equivalent Cs(2), and two equivalent Hg(3) atoms to form a mixture of distorted face and corner-sharing ClCs4Hg2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the third Cl site, Cl(1) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), two equivalent Cs(2), and one Hg(2) atom. In the fourth Cl site, Cl(2) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), two equivalent Cs(2), and one Hg(1) atom. In the fifth Cl site, Cl(3) is bonded to one Cs(1), one Cs(3), two equivalent Cs(2), one Hg(2), and one Hg(3) atom to form a mixture of distorted face, corner, and edge-sharing ClCs4Hg2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the sixth Cl site, Cl(4) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), two equivalent Cs(2), one Hg(2), and one Hg(3) atom.
CsHgCl3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), two equivalent Cl(4), two equivalent Cl(5), and two equivalent Cl(6) atoms to form CsCl12 cuboctahedra that share corners with four equivalent Cs(3)Cl12 cuboctahedra, corners with eight equivalent Cs(2)Cl12 cuboctahedra, edges with two equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(3)Cl12 cuboctahedra, faces with four equivalent Cs(2)Cl12 cuboctahedra, faces with two equivalent Hg(2)Cl6 octahedra, and faces with two equivalent Hg(3)Cl5 square pyramids. Both Cs(1)-Cl(1) bond lengths are 4.00 Å. Both Cs(1)-Cl(2) bond lengths are 3.91 Å. Both Cs(1)-Cl(3) bond lengths are 3.88 Å. Both Cs(1)-Cl(4) bond lengths are 3.88 Å. Both Cs(1)-Cl(5) bond lengths are 3.88 Å. Both Cs(1)-Cl(6) bond lengths are 3.92 Å. In the second Cs site, Cs(2) is bonded to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), two equivalent Cl(4), two equivalent Cl(5), and two equivalent Cl(6) atoms to form CsCl12 cuboctahedra that share corners with four equivalent Cs(1)Cl12 cuboctahedra, corners with four equivalent Cs(2)Cl12 cuboctahedra, corners with four equivalent Cs(3)Cl12 cuboctahedra, edges with two equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(1)Cl12 cuboctahedra, faces with two equivalent Cs(2)Cl12 cuboctahedra, faces with two equivalent Cs(3)Cl12 cuboctahedra, faces with two equivalent Hg(2)Cl6 octahedra, and faces with two equivalent Hg(3)Cl5 square pyramids. There is one shorter (3.93 Å) and one longer (3.96 Å) Cs(2)-Cl(1) bond length. There is one shorter (3.94 Å) and one longer (3.95 Å) Cs(2)-Cl(2) bond length. There is one shorter (3.90 Å) and one longer (3.95 Å) Cs(2)-Cl(3) bond length. There is one shorter (3.88 Å) and one longer (3.98 Å) Cs(2)-Cl(4) bond length. There is one shorter (3.81 Å) and one longer (3.88 Å) Cs(2)-Cl(5) bond length. There is one shorter (3.79 Å) and one longer (4.04 Å) Cs(2)-Cl(6) bond length. In the third Cs site, Cs(3) is bonded to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), two equivalent Cl(4), two equivalent Cl(5), and two equivalent Cl(6) atoms to form CsCl12 cuboctahedra that share corners with four equivalent Cs(1)Cl12 cuboctahedra, corners with eight equivalent Cs(2)Cl12 cuboctahedra, edges with two equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(1)Cl12 cuboctahedra, faces with four equivalent Cs(2)Cl12 cuboctahedra, faces with two equivalent Hg(2)Cl6 octahedra, and faces with two equivalent Hg(3)Cl5 square pyramids. Both Cs(3)-Cl(1) bond lengths are 3.86 Å. Both Cs(3)-Cl(2) bond lengths are 3.88 Å. Both Cs(3)-Cl(3) bond lengths are 3.92 Å. Both Cs(3)-Cl(4) bond lengths are 3.86 Å. Both Cs(3)-Cl(5) bond lengths are 4.00 Å. Both Cs(3)-Cl(6) bond lengths are 3.94 Å. There are three inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a distorted square co-planar geometry to two equivalent Cl(2) and two equivalent Cl(5) atoms. Both Hg(1)-Cl(2) bond lengths are 2.47 Å. Both Hg(1)-Cl(5) bond lengths are 2.71 Å. In the second Hg site, Hg(2) is bonded to two equivalent Cl(1), two equivalent Cl(3), and two equivalent Cl(4) atoms to form distorted HgCl6 octahedra that share corners with four equivalent Hg(3)Cl5 square pyramids, faces with two equivalent Cs(1)Cl12 cuboctahedra, faces with two equivalent Cs(3)Cl12 cuboctahedra, and faces with four equivalent Cs(2)Cl12 cuboctahedra. Both Hg(2)-Cl(1) bond lengths are 2.38 Å. Both Hg(2)-Cl(3) bond lengths are 2.96 Å. Both Hg(2)-Cl(4) bond lengths are 3.04 Å. In the third Hg site, Hg(3) is bonded to one Cl(3), one Cl(4), one Cl(5), and two equivalent Cl(6) atoms to form HgCl5 square pyramids that share corners with two equivalent Hg(2)Cl6 octahedra, corners with two equivalent Hg(3)Cl5 square pyramids,  an edgeedge with one Cs(1)Cl12 cuboctahedra,  an edgeedge with one Cs(3)Cl12 cuboctahedra, edges with two equivalent Cs(2)Cl12 cuboctahedra,  a faceface with one Cs(1)Cl12 cuboctahedra,  a faceface with one Cs(3)Cl12 cuboctahedra, and faces with two equivalent Cs(2)Cl12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-5°. The Hg(3)-Cl(3) bond length is 2.55 Å. The Hg(3)-Cl(4) bond length is 2.55 Å. The Hg(3)-Cl(5) bond length is 2.72 Å. Both Hg(3)-Cl(6) bond lengths are 2.75 Å. There are six inequivalent Cl sites. In the first Cl site, Cl(5) is bonded to one Cs(1), one Cs(3), two equivalent Cs(2), one Hg(1), and one Hg(3) atom to form a mixture of distorted face, corner, and edge-sharing ClCs4Hg2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second Cl site, Cl(6) is bonded to one Cs(1), one Cs(3), two equivalent Cs(2), and two equivalent Hg(3) atoms to form a mixture of distorted face and corner-sharing ClCs4Hg2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the third Cl site, Cl(1) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), two equivalent Cs(2), and one Hg(2) atom. In the fourth Cl site, Cl(2) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), two equivalent Cs(2), and one Hg(1) atom. In the fifth Cl site, Cl(3) is bonded to one Cs(1), one Cs(3), two equivalent Cs(2), one Hg(2), and one Hg(3) atom to form a mixture of distorted face, corner, and edge-sharing ClCs4Hg2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the sixth Cl site, Cl(4) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), two equivalent Cs(2), one Hg(2), and one Hg(3) atom.