Mercury silvering 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 toxic, especially in its vapor phase. Mercury silvering can be detected through a variety of
Mercury(I) iodide Mercury(I) iodide Mercury(I) iodide is a chemical compound of mercury and iodine. The chemical formula is HgI. It is photosensitive and decomposes easily to mercury and HgI. Mercury(I) iodide can be prepared by directly reacting mercury and iodine. In common with other Hg(I) (mercurous) compounds which contain linear X-Hg-Hg-X units, HgI contains linear IHgI units with an Hg-Hg bond length of 272 pm (Hg-Hg in the metal is 300 pm) and an Hg-I bond length of 268 pm. The overall coordination of each Hg atom is octahedral as it has in addition to the two nearest neighbours there are four