HgCr2S4 crystallizes in the monoclinic P2/m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form edge-sharing CrS6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form edge-sharing CrS6 octahedra. Hg(1) is bonded in a linear geometry to two equivalent S(1) atoms. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Cr(2), two equivalent Cr(1), and one Hg(1) atom to form a mixture of corner and edge-sharing SCr3Hg trigonal pyramids. In the second S site, S(2) is bonded in a distorted T-shaped geometry to one Cr(1) and two equivalent Cr(2) atoms.
HgCr2S4 crystallizes in the monoclinic P2/m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form edge-sharing CrS6 octahedra. Both Cr(1)-S(2) bond lengths are 2.42 Å. All Cr(1)-S(1) bond lengths are 2.40 Å. In the second Cr site, Cr(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form edge-sharing CrS6 octahedra. Both Cr(2)-S(1) bond lengths are 2.39 Å. All Cr(2)-S(2) bond lengths are 2.42 Å. Hg(1) is bonded in a linear geometry to two equivalent S(1) atoms. Both Hg(1)-S(1) bond lengths are 2.47 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Cr(2), two equivalent Cr(1), and one Hg(1) atom to form a mixture of corner and edge-sharing SCr3Hg trigonal pyramids. In the second S site, S(2) is bonded in a distorted T-shaped geometry to one Cr(1) and two equivalent Cr(2) atoms.