DOE OSTI2020
HgWO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 29–38°. There are a spread of W–O bond distances ranging from 1.84–2.23 Å. In the second W6+ site, W6+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 29–38°. There are a spread of W–O bond distances ranging from 1.76–2.24 Å. There are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hg–O bond distances ranging from 2.26–2.98 Å. In the second Hg2+ site, Hg2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Hg–O bond distances ranging from 2.24–2.87 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two W6+ and two Hg2+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one W6+ and one Hg2+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two W6+ and one Hg2+ atom. In the fourth O2- site, O2- is bonded to two equivalent W6+ and two Hg2+ atoms to form edge-sharing OHg2W2 tetrahedra. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one W6+ and three Hg2+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one W6+ and two Hg2+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent W6+ and two Hg2+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one W6+ and two Hg2+ atoms.