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 (dentistry) conservative preparation would be beneficial, composite is the recommended restorative material. These situations would include small occlusal restorations, in which amalgam would require the removal of more sound tooth structure, as well as in "enamel sites beyond the height of contour". For cosmetic purposes, composite is preferred when a restoration is required on an immediately visible portion of a tooth. Dental amalgam does not by itself bond to tooth structure. This was recognized as a shortcoming by early practitioners such as Baldwin. He recommended that the prepared cavity be coated with zinc phosphate cement just prior to filling with amalgam,