The major applications of mercury are in electrical equipment and in control devices, where the fluidity stability, high density and electrical conductivity are essential. This metal is also used in the agriculture (as fungicide and bactericide), in dental preparations, in the electrolytic preparation of chlorine and alkalis, in pharmaceuticals, etc.
The mercury compounds have more limited applications than the metal. The mercurous chloride (calomel) is one of the oldest known pharmaceuticals; it is still used as antiseptic. The red mercury oxide is used in mercury batteries, developed during II World War, which are compact and stable energy sources. The mercuric chloride prevents attacks of fungus in seeds, bulbs and it is good to amalgamate aluminum, zinc and other metals.
The organic compounds that contain mercury are commercially important as microbial agents.