HgTlAsS3 crystallizes in the tetragonal I-42m space group. Hg(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form distorted HgS4 tetrahedra that share corners with two equivalent Hg(1)S4 tetrahedra and corners with two equivalent Tl(2)S4 tetrahedra. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a distorted L-shaped geometry to two equivalent S(2) atoms. In the second Tl site, Tl(2) is bonded to four equivalent S(1) atoms to form TlS4 tetrahedra that share corners with four equivalent Hg(1)S4 tetrahedra. As(1) is bonded in a distorted T-shaped geometry to one S(2) and two equivalent S(1) atoms. There are two inequivalent S sites. In the first S site, S(2) is bonded to two equivalent Hg(1), one Tl(1), and one As(1) atom to form corner-sharing STlHg2As tetrahedra. In the second S site, S(1) is bonded in a distorted trigonal non-coplanar geometry to one Hg(1), one Tl(2), and one As(1) atom.
HgTlAsS3 crystallizes in the tetragonal I-42m space group. Hg(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form distorted HgS4 tetrahedra that share corners with two equivalent Hg(1)S4 tetrahedra and corners with two equivalent Tl(2)S4 tetrahedra. Both Hg(1)-S(1) bond lengths are 2.55 Å. Both Hg(1)-S(2) bond lengths are 2.83 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a distorted L-shaped geometry to two equivalent S(2) atoms. Both Tl(1)-S(2) bond lengths are 2.92 Å. In the second Tl site, Tl(2) is bonded to four equivalent S(1) atoms to form TlS4 tetrahedra that share corners with four equivalent Hg(1)S4 tetrahedra. All Tl(2)-S(1) bond lengths are 3.02 Å. As(1) is bonded in a distorted T-shaped geometry to one S(2) and two equivalent S(1) atoms. The As(1)-S(2) bond length is 2.35 Å. Both As(1)-S(1) bond lengths are 2.27 Å. There are two inequivalent S sites. In the first S site, S(2) is bonded to two equivalent Hg(1), one Tl(1), and one As(1) atom to form corner-sharing STlHg2As tetrahedra. In the second S site, S(1) is bonded in a distorted trigonal non-coplanar geometry to one Hg(1), one Tl(2), and one As(1) atom.