Natural History (Pliny) developed for counterfeit coins and proved very popular with the victims, mostly ordinary people. He deals with the liquid metal mercury, also found in silver mines. He records that it is toxic, and amalgamates with gold, so is used for refining and extracting that metal. He says mercury is used for gilding copper, while antimony is found in silver mines and is used as an eyebrow cosmetic. The main ore of mercury is cinnabar, long used as a pigment by painters. He says that the colour is similar to "scolecium", probably the kermes insect. The dust is very toxic, so
Metal ammine complex is ammonia (pK ~ 33). For highly cationic complexes such as [Pt(NH)], the conjugate base can be obtained. The deprotonation of cobalt(III) ammine-halide complexes, e.g. [CoCl(NH)] labilises the Co-Cl bond, according to the Sn1CB mechanism. Metal ammine complexes find many uses. Cisplatin (PtCl(NH)) is a coordination compound containing two chloro and two ammine ligands. This is a drug used in treating cancer. Many other amine complexes of the platinum group metals have been evaluated for this application. In the separation of the individual platinum metals from their ore, several schemes rely on the precipitation of [RhCl(NH)]Cl. In some separation schemes,