Hg(pyridine)2][Cr2O7], a compound used for a quick assay method to quantify soluble HgIIions

Abstract

The title compound, bis­(pyridine-N)­mercury(II) dichrom­ate(VI), [Hg(C5H5N)2][Cr2O7], is the first structurally determined representative of metal dichromates with additional pyridine ligands of general formula [M(py)n]mCr2O7 (py = pyridine) and can be used for a quick assay method to quantify HgII ions in solution. Two distinct Hg atoms, both located on special positions with symmetry 2 and \overline 1, respectively, are coordinated octahedrally by two axial N atoms of pyridine rings at short distances \overline {\it d}(Hg—N) = 2.101 A and four equatorial O atoms of dichromate groups at longer distances \overline {\it d}(Hg—O) = 2.620 A. The dichromate group has a skew conformation with a bridging angle of 138.62 (17)°.