Mercury silvering methods. The technique was also used in Asia, for example "tokin" plating in Edo-period Japan. Mercury silvering Mercury silvering or fire gilding is a silvering technique for applying a thin layer of precious metal such as silver or gold (mercury gilding) to a base metal object. The process was invented during the Middle Ages and is documented in Vannoccio Biringuccio's 1540 book "De la pirotechnia". An amalgam of mercury and the precious metal is prepared and applied to the object which is then heated, sometimes in oil, vaporizing most of the mercury. The technique is dangerous since mercury is highly
Mercury(II) cyanide evaporated to crystallize the product. Hg(CN) can also be prepared by mixing HgO, finely powdered Prussian blue. In addition, it can be produced by reacting mercuric sulfate with potassium ferrocyanide in water: Another method to generate mercuric cyanide is through the disproportionation of mercury(I) derivatives. In these reactions, metallic mercury precipitates, and Hg(CN) remains in solution: Mercury cyanide can be used as a promoter in the Koenigs–Knorr reaction for the synthesis of glycosides. Cyanogen, (CN), forms upon heating dry mercury cyanide but the method is inferior to other routes: Coordination polymers can be synthesized from Hg(CN) building blocks. Large single