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
Barbier reaction aqueous ammonium chloride solution added later to quench the reaction): the intramolecular Barbier reaction with samarium(II) iodide: the reaction of an allyl bromide with formaldehyde in THF with indium powder: or another allyl bromide in a reaction with benzaldehyde and zinc powder in water: The synthesis of (+)-aspicillin, starts first with a hydroboration, then transmetallation to zinc which can then do an addition into the aldehyde substituent. Barbier reaction The Barbier reaction is an organometallic reaction between an alkyl halide(chloride, bromide, iodide), a carbonyl group and a metal. The reaction can be performed using magnesium, aluminium, zinc, indium, tin, samarium,