Mercury Chemistry: Hg2[CrO4] disproportionation in KCN

In this video, we will react the Hg2[CrO4] we made in the previous video with an excess of KCN. As we have already shown in our video on the reaction of HgO with Prussian blue the mercury likes to form a cyanide complex. So we expect something like Mercury(I)cyanide to be forming. This compound, however, is unstable and quickly disproportionates to form elemental mercury and Hg(CN)2. You can see the black Hg particles sink to the bottom of the tube.