Mercury(I) bromide

Mercury(I) bromide, also known as mercurous bromide, is a chemical compound. Its chemical formula is Hg2Br2. It has mercury and bromide ions in it. The mercury is in its +1 oxidation state.
Properties.
Mercury(I) bromide is a white crystalline solid. It is highly toxic. It easily disproportionates to mercury(II) bromide and mercury metal. 
Occurrence.
It is found very rarely as kuzminite, a mercury(I) bromide and chloride.
Preparation.
It is made by reacting a bromide like potassium bromide or sodium bromide with mercury(I) nitrate. It can also be made by reacting mercury and bromine.