Materials Data on Hg4As2O7 by Materials Project
Hg4As2O7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a distorted single-bond geometry to one O2- atom. The Hg–O bond length is 2.17 Å. In the second Hg2+ site, Hg2+ is bonded in a 5-coordinate geometry to one Hg2+ and four O2- atoms. The Hg–Hg bond length is 2.60 Å. There are a spread of Hg–O bond distances ranging from 2.31–2.98 Å. There are two inequivalent As3+ sites. In the first As3+ site, As3+ is bonded to four O2- atoms to form corner-sharing AsO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.70–1.84 Å. In the second As3+ site, As3+ is bonded to four O2- atoms to form corner-sharing AsO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.70–1.79 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Hg2+ and one As3+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Hg2+ and one As3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Hg2+ and one As3+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two equivalent Hg2+ and one As3+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two As3+ atoms.