Reductants metal mercaptides

Owing to the reductant nature of thiols, a change in the oxidation number of the metallic ions can be observed before the mercaptide precipitation [e.g., Au(III) ions are reduced to Au(I) before mercaptide precipitation]. In addition, in the case of polyvalent metals, intermediate reaction products can be obtained, since the mercaptide formation takes place by steps. For example, chlorides of alkylmercaptomercury can be obtained from the reaction of thiols with mercury chloride ... 

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