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,
Dental amalgam controversy condoned the use of dental amalgam. In 1855, Dr. J. Foster Flagg, a professor of dental pathology in Philadelphia, experimented with new mixtures of amalgam. In 1861, he presented his findings to the Pennsylvania Association of Dental Surgeons and, in 1881, he published his book, Plastic and Plastic Fillings (Figure 4). (Amalgam fillings were often called "plastic fillings" at the time.) The inevitable result of this affair was that silver amalgam was proven to be, "an excellent filling material," and expanded dentistry's, "ability to save teeth." Around the same time, John and Charles Tomes in England conducted research on the