The chemical element mercury has the atomic number 80 and the symbol Hg. In the past, it was known as hydrargyrum, a compound of the Greek terms hydor and argyros, and quicksilver. The only other metallic element that is known to be liquid under normal circumstances for temperature and pressure is the halogen bromine, while metals like caesium, gallium, and rubidium melt slightly above room temperature. Mercury is a heavy, silvery d-block element.
World-wide deposits of mercury, mostly as cinnabar, are found (mercuric sulfide). Grinding either synthetic mercuric sulfide or natural cinnabar yields the red color vermilion.
Mercury is used in a variety of devices, including thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps, and others. However, due to worries about the element's toxicity, mercury thermometers and sphygmomanometers have been largely phased out in clinical settings in favor of substitutes like alcohol- or galinstan-filled glass thermometers and thermistor- or Likewise, mercury sphygmomanometers have been replaced with mechanical pressure gauges and electrical strain gauge sensors.
Mercury poisoning may happen when someone is exposed to water-soluble forms of the metal, when they breathe mercury vapor, or when they consume mercury in any form.
