Electricity passed through mercury vapor in a fluorescent lamp produces short-wave ultraviolet light, which then causes the phosphor in the tube to fluoresce, making visible light. Mercury remains in use in scientific research applications and in amalgam for dental restoration in some locales. Likewise, mechanical pressure gauges and electronic strain gauge sensors have replaced mercury sphygmomanometers. Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps and other devices, though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alternatives such as alcohol- or galinstan-filled glass thermometers and thermistor- or infrared-based electronic instruments. The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide.
Mercury occurs in deposits throughout the world mostly as cinnabar ( mercuric sulfide).
A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard conditions for temperature and pressure the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature.
It is also known as quicksilver and was formerly named hydrargyrum ( / h aɪ ˈ d r ɑːr dʒ ər ə m/ hy- DRAR-jər-əm) from the Greek words, hydor (water) and argyros (silver). Mercury is a chemical element with the symbol Hg and atomic number 80.
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