Mercury (element)

Mercury (element), chemical element, symbol Hg; for physical constants see Periodic Table. Mercury was known to the ancient Chinese and Hindus. It is a silvery-white, heavy, liquid metal. Compared with other metals, it is a poor conductor of heat and a fair conductor of electricity. Mercury is the only common metal that is liquid at ordinary temperatures. It easily forms alloys with many other metals. Both the element and most of its compounds are poisonous. Mercury and its compounds are used in electrolytic cells, dentistry, thermometers, barometers, diffusion pumps, electrical switches, mercury-vapor lamps, paint, batteries, explosive detonators, and in medicine.