BaHgS2 crystallizes in the orthorhombic Pmc2_1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one S(2), two equivalent S(3), and four equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing BaS7 pentagonal bipyramids. In the second Ba site, Ba(2) is bonded to one S(2), two equivalent S(3), and four equivalent S(1) atoms to form a mixture of distorted edge, face, and corner-sharing BaS7 pentagonal bipyramids. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a linear geometry to one S(1) and one S(3) atom. In the second Hg site, Hg(2) is bonded in a distorted trigonal planar geometry to two equivalent S(2) and two equivalent S(4) atoms. There are four inequivalent S sites. In the first S site, S(1) is bonded to four equivalent Ba(2) and one Hg(1) atom to form a mixture of distorted edge and corner-sharing SBa4Hg square pyramids. In the second S site, S(2) is bonded in a see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Hg(2) atoms. In the third S site, S(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), and one Hg(1) atom to form distorted SBa4Hg square pyramids that share corners with four equivalent S(4)Ba4Hg2 octahedra, corners with five equivalent S(1)Ba4Hg square pyramids, edges with two equivalent S(4)Ba4Hg2 octahedra, edges with two equivalent S(1)Ba4Hg square pyramids, and edges with two equivalent S(3)Ba4Hg square pyramids. The corner-sharing octahedral tilt angles range from 19-56°. In the fourth S site, S(4) is bonded to four equivalent Ba(1) and two equivalent Hg(2) atoms to form distorted SBa4Hg2 octahedra that share corners with four equivalent S(4)Ba4Hg2 octahedra, corners with four equivalent S(3)Ba4Hg square pyramids, edges with two equivalent S(4)Ba4Hg2 octahedra, edges with two equivalent S(3)Ba4Hg square pyramids, and faces with two equivalent S(4)Ba4Hg2 octahedra. The corner-sharing octahedral tilt angles are 55°.
BaHgS2 crystallizes in the orthorhombic Pmc2_1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one S(2), two equivalent S(3), and four equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing BaS7 pentagonal bipyramids. The Ba(1)-S(2) bond length is 3.36 Å. Both Ba(1)-S(3) bond lengths are 3.27 Å. All Ba(1)-S(4) bond lengths are 3.20 Å. In the second Ba site, Ba(2) is bonded to one S(2), two equivalent S(3), and four equivalent S(1) atoms to form a mixture of distorted edge, face, and corner-sharing BaS7 pentagonal bipyramids. The Ba(2)-S(2) bond length is 3.27 Å. Both Ba(2)-S(3) bond lengths are 3.26 Å. There are two shorter (3.25 Å) and two longer (3.34 Å) Ba(2)-S(1) bond lengths. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a linear geometry to one S(1) and one S(3) atom. The Hg(1)-S(1) bond length is 2.36 Å. The Hg(1)-S(3) bond length is 2.36 Å. In the second Hg site, Hg(2) is bonded in a distorted trigonal planar geometry to two equivalent S(2) and two equivalent S(4) atoms. Both Hg(2)-S(2) bond lengths are 2.56 Å. There is one shorter (2.48 Å) and one longer (3.08 Å) Hg(2)-S(4) bond length. There are four inequivalent S sites. In the first S site, S(1) is bonded to four equivalent Ba(2) and one Hg(1) atom to form a mixture of distorted edge and corner-sharing SBa4Hg square pyramids. In the second S site, S(2) is bonded in a see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Hg(2) atoms. In the third S site, S(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), and one Hg(1) atom to form distorted SBa4Hg square pyramids that share corners with four equivalent S(4)Ba4Hg2 octahedra, corners with five equivalent S(1)Ba4Hg square pyramids, edges with two equivalent S(4)Ba4Hg2 octahedra, edges with two equivalent S(1)Ba4Hg square pyramids, and edges with two equivalent S(3)Ba4Hg square pyramids. The corner-sharing octahedral tilt angles range from 19-56°. In the fourth S site, S(4) is bonded to four equivalent Ba(1) and two equivalent Hg(2) atoms to form distorted SBa4Hg2 octahedra that share corners with four equivalent S(4)Ba4Hg2 octahedra, corners with four equivalent S(3)Ba4Hg square pyramids, edges with two equivalent S(4)Ba4Hg2 octahedra, edges with two equivalent S(3)Ba4Hg square pyramids, and faces with two equivalent S(4)Ba4Hg2 octahedra. The corner-sharing octahedral tilt angles are 55°.