DOE OSTI2020
Hg19(As5Br9)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are ten inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to two equivalent As2- and four Br1- atoms to form HgAs2Br4 octahedra that share corners with two equivalent HgAs2Br5 pentagonal bipyramids, corners with two equivalent AsHg3As tetrahedra, and edges with two equivalent HgAs2Br4 octahedra. Both Hg–As bond lengths are 2.63 Å. There are two shorter (3.18 Å) and two longer (3.23 Å) Hg–Br bond lengths. In the second Hg2+ site, Hg2+ is bonded to two As2- and four Br1- atoms to form HgAs2Br4 octahedra that share a cornercorner with one HgAs2Br5 pentagonal bipyramid, corners with two AsHg3As tetrahedra, an edgeedge with one HgAs2Br4 octahedra, and an edgeedge with one HgAs2Br5 pentagonal bipyramid. Both Hg–As bond lengths are 2.60 Å. There are a spread of Hg–Br bond distances ranging from 3.24–3.56 Å. In the third Hg2+ site, Hg2+ is bonded in a distorted rectangular see-saw-like geometry to one As2- and three Br1- atoms. The Hg–As bond length is 2.56 Å. There are a spread of Hg–Br bond distances ranging from 2.60–3.00 Å. In the fourth Hg2+ site, Hg2+ is bonded to two As2- and five Br1- atoms to form HgAs2Br5 pentagonal bipyramids that share corners with two HgAs2Br4 octahedra, a cornercorner with one AsHg3As tetrahedra, and an edgeedge with one HgAs2Br4 octahedra. The corner-sharing octahedra tilt angles range from 34–89°. There are one shorter (2.59 Å) and one longer (2.61 Å) Hg–As bond lengths. There are a spread of Hg–Br bond distances ranging from 3.24–3.45 Å. In the fifth Hg2+ site, Hg2+ is bonded in a 6-coordinate geometry to one As2- and five Br1- atoms. The Hg–As bond length is 2.57 Å. There are a spread of Hg–Br bond distances ranging from 2.63–3.50 Å. In the sixth Hg2+ site, Hg2+ is bonded in a 7-coordinate geometry to two As2- and five Br1- atoms. Both Hg–As bond lengths are 2.60 Å. There are a spread of Hg–Br bond distances ranging from 3.21–3.69 Å. In the seventh Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to one As2- and four Br1- atoms. The Hg–As bond length is 2.56 Å. There are a spread of Hg–Br bond distances ranging from 2.57–3.58 Å. In the eighth Hg2+ site, Hg2+ is bonded in a 4-coordinate geometry to two As2- and two Br1- atoms. There are one shorter (2.57 Å) and one longer (2.61 Å) Hg–As bond lengths. There are one shorter (3.41 Å) and one longer (3.63 Å) Hg–Br bond lengths. In the ninth Hg2+ site, Hg2+ is bonded in a 4-coordinate geometry to one As2- and three Br1- atoms. The Hg–As bond length is 2.58 Å. There are a spread of Hg–Br bond distances ranging from 2.69–2.89 Å. In the tenth Hg2+ site, Hg2+ is bonded in a 2-coordinate geometry to one As2- and five Br1- atoms. The Hg–As bond length is 2.54 Å. There are a spread of Hg–Br bond distances ranging from 2.56–3.64 Å. There are five inequivalent As2- sites. In the first As2- site, As2- is bonded to three Hg2+ and one As2- atom to form AsHg3As tetrahedra that share a cornercorner with one HgAs2Br4 octahedra, a cornercorner with one HgAs2Br5 pentagonal bipyramid, and corners with two AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 72°. The As–As bond length is 2.47 Å. In the second As2- site, As2- is bonded to three Hg2+ and one As2- atom to form corner-sharing AsHg3As tetrahedra. The As–As bond length is 2.46 Å. In the third As2- site, As2- is bonded to three Hg2+ and one As2- atom to form corner-sharing AsHg3As tetrahedra. The As–As bond length is 2.49 Å. In the fourth As2- site, As2- is bonded to three Hg2+ and one As2- atom to form AsHg3As tetrahedra that share corners with two HgAs2Br4 octahedra and a cornercorner with one AsHg3As tetrahedra. The corner-sharing octahedra tilt angles range from 70–71°. In the fifth As2- site, As2- is bonded in a 3-coordinate geometry to two Hg2+ and one As2- atom. There are nine inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 1-coordinate geometry to four Hg2+ atoms. In the second Br1- site, Br1- is bonded in a 4-coordinate geometry to four Hg2+ atoms. In the third Br1- site, Br1- is bonded in a 5-coordinate geometry to five Hg2+ atoms. In the fourth Br1- site, Br1- is bonded in a 5-coordinate geometry to five Hg2+ atoms. In the fifth Br1- site, Br1- is bonded in a 5-coordinate geometry to five Hg2+ atoms. In the sixth Br1- site, Br1- is bonded in a 4-coordinate geometry to four Hg2+ atoms. In the seventh Br1- site, Br1- is bonded in a 1-coordinate geometry to four Hg2+ atoms. In the eighth Br1- site, Br1- is bonded in a distorted single-bond geometry to four Hg2+ atoms. In the ninth Br1- site, Br1- is bonded in a distorted single-bond geometry to three Hg2+ atoms.