Amalgam (chemistry) organic synthesis (e.g., for the Clemmensen reduction). It is the reducing agent in the Jones reductor, used in analytical chemistry. Formerly the zinc plates of dry batteries were amalgamated with a little mercury to prevent deterioration in storage. It is a binary solution (liquid-solid) of mercury and zinc. For the alkali metals, amalgamation is exothermic, and distinct chemical forms can be identified, such as KHg and KHg. KHg is a gold-coloured compound with a melting point of 178 °C, and KHg a silver-coloured compound with a melting point of 278 °C. These amalgams are very sensitive to air and water,
Amalgam tattoo of discolored mucosa is much larger. If necessary, the diagnosis can be confirmed histologically by excisional biopsy, which excludes nevi and melanomas. If a biopsy is taken, the histopathologic appearance is: Theoretically, routine use of a dental dam during dental procedures which involve amalgam should reduce the risk of amalgam tattoo. No treatment is required since the lesion is entirely benign. Some suggest that amalgam tattoos are best surgically excised so as to ensure the lesion does not represent a melanoma. Other say that excision should only be carried out if there is any doubt over the diagnosis, and that