Materials Data on Cr2HgN2Cl2O7 by Materials Project
Cr2HgO7Cl2N2 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of eight ammonia molecules and two Cr2HgO7Cl2 ribbons oriented in the (0, 1, 0) direction. In each Cr2HgO7Cl2 ribbon, there are two inequivalent Cr6+ sites. In the first Cr6+ site, Cr6+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.63–1.78 Å. In the second Cr6+ site, Cr6+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.63–1.79 Å. Hg2+ is bonded in a 5-coordinate geometry to three O2- and two Cl1- atoms. There are a spread of Hg–O bond distances ranging from 2.86–2.93 Å. There are one shorter (2.31 Å) and one longer (2.33 Å) Hg–Cl bond lengths. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Cr6+ and one Hg2+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Cr6+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Cr6+ and one Hg2+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Cr6+ and one Hg2+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one Cr6+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one Cr6+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two Cr6+ atoms. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Hg2+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Hg2+ atom.