Materials Data on Cr2Hg2O9 by Materials Project
Cr2Hg2O9 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of two Cr2Hg2O9 sheets oriented in the (0, 0, 1) direction. Cr is bonded in a tetrahedral geometry to four O atoms. There is two shorter (1.62 Å) and two longer (1.74 Å) Cr–O bond length. Hg is bonded in a 2-coordinate geometry to three O atoms. There are two shorter (2.09 Å) and one longer (2.54 Å) Hg–O bond lengths. There are five inequivalent O sites. In the first O site, O is bonded in an L-shaped geometry to two equivalent Hg atoms. In the second O site, O is bonded in a bent 120 degrees geometry to one Cr and one Hg atom. In the third O site, O is bonded in a single-bond geometry to one Cr atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one Cr and one Hg atom. In the fifth O site, O is bonded in a single-bond geometry to one Cr atom.