Upon freezing, the volume of mercury decreases by 3.59% and its density changes from 13.69 g/cm 3 when liquid to 14.184 g/cm 3 when solid. This effect is due to lanthanide contraction and relativistic contraction reducing the radius of the outermost electrons, and thus weakening the metallic bonding in mercury. It has a freezing point of −38.83 ☌ and a boiling point of 356.73 ☌, both the lowest of any stable metal, although preliminary experiments on copernicium and flerovium have indicated that they have even lower boiling points. Compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity. Mercury is a heavy, silvery-white liquid metal. Mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury), by inhalation of mercury vapor, or by ingesting any form of mercury.Īn old pound coin (density ~7.6 g/cm 3) floats on mercury due to the combination of the buoyant force and surface tension. 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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