Materials Data on BaHgAs2O7 by Materials Project
BaHgAs2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.75–3.15 Å. Hg2+ is bonded to six O2- atoms to form distorted HgO6 octahedra that share corners with six AsO4 tetrahedra and an edgeedge with one HgO6 octahedra. There are a spread of Hg–O bond distances ranging from 2.29–2.68 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent HgO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–63°. There are a spread of As–O bond distances ranging from 1.69–1.80 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent HgO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–63°. There are a spread of As–O bond distances ranging from 1.69–1.81 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+, one Hg2+, and one As5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one As5+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ba2+, one Hg2+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, two equivalent Hg2+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+, one Hg2+, and one As5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, one Hg2+, and one As5+ atom.