Materials Data on BaHgS2 by Materials Project
BaHgS2 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to seven S2- atoms to form a mixture of distorted corner, edge, and face-sharing BaS7 pentagonal bipyramids. There are a spread of Ba–S bond distances ranging from 3.22–3.39 Å. In the second Ba2+ site, Ba2+ is bonded to seven S2- atoms to form a mixture of distorted corner, edge, and face-sharing BaS7 pentagonal bipyramids. There are a spread of Ba–S bond distances ranging from 3.26–3.36 Å. There are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to five S2- atoms. There are two shorter (2.38 Å) and three longer (3.33 Å) Hg–S bond lengths. In the second Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to five S2- atoms. There are a spread of Hg–S bond distances ranging from 2.50–3.48 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to four equivalent Ba2+ and two equivalent Hg2+ atoms. In the second S2- site, S2- is bonded to two Ba2+ and four Hg2+ atoms to form distorted SBa2Hg4 octahedra that share corners with four equivalent SBa4Hg2 octahedra and edges with four SBa2Hg4 octahedra. The corner-sharing octahedra tilt angles range from 42–57°. In the third S2- site, S2- is bonded in a 5-coordinate geometry to four Ba2+ and two Hg2+ atoms. In the fourth S2- site, S2- is bonded to four equivalent Ba2+ and two equivalent Hg2+ atoms to form distorted SBa4Hg2 octahedra that share corners with eight SBa2Hg4 octahedra, edges with four SBa2Hg4 octahedra, and faces with two equivalent SBa4Hg2 octahedra. The corner-sharing octahedra tilt angles range from 42–57°.