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
Metal carbonyl hydride the catalyst is usually formed "in situ" in a reaction of a metal salt precursor with the syngas. The hydroformylation starts with the generation of a coordinatively unsaturated 16-electron metal carbonyl hydride complex like HCo(CO) or HRh(CO)(PPh) by dissociation of a ligand. Such complexes bind olefins in a first step via π-complexation. In a second step an alkyl complex is formed by insertion of the olefin into the metal-hydrogen bond, leading once again to a 16-electron species. This complex can bind another carbon monoxide, which can insert into the metal-carbon bond of the alkyl ligand to form an acyl complex.