mercury

For the planet, see Mercury.

Mercury, also called quicksilver, is a chemical element in the periodic table that has the symbol Hg (from the Latin hydrargyrum, for watery (or liquid) silver) and atomic number 80. A heavy, silvery, transition metal, mercury is one of five elements that are liquid at or near room temperature (the others are the metals caesium, francium, and gallium, and the nonmetal bromine). Mercury is used in thermometers, barometers and other scientific apparatus, although the use of mercury in thermometers has been largely phased out in clinical and scientific environments (in favor of alcohol-filled, digital or thermistor-based replacements) in the interests of health and safety due to the toxicity of the element. Mercury is mostly obtained by reduction from the mineral cinnabar. Its high density allows things such as billiard balls to float with less than 20% of their volume submerged.