mercury

mercury or quicksilver [from the Roman god Mercury], metallic chemical element; symbol Hg [Lat. hydrargyrum=liquid silver]; at. no. 80; at. wt. 200.59; m.p. -38.842°C;; b.p. 356.58°C;; sp. gr. 13.55 at 20°C;; valence +1 or +2. Mercury was discovered in antiquity, and was known to the ancient Chinese, Hindus, and Egyptians, but was not recognized as an element. It was used as a medicine by Paracelsus. It was first recognized as a chemical element (in the modern sense) by A. L. Lavoisier about the end of the 18th cent.

Properties

Mercury is the only common metal existing as a liquid at ordinary temperatures. The pure metal has a silver-white mirrorlike appearance. Mercury is below cadmium in Group 2 of the periodic table. It is relatively stable in dry air, but in moist air slowly forms a gray oxide coating. Mercury has high surface tension; when spilled, it breaks up into tiny beads which often become lodged in cracks.

Compounds

Mercury forms numerous compounds, assuming +1 valence in mercurous compounds and +2 valence in mercuric compounds. Mercury is not attacked by dilute hydrochloric or sulfuric acid. It reacts with hot nitric acid to form mercuric nitrate, Hg(No₃)₂. An excess of mercury reacts with nitric acid to form mercurous nitrate, HgNO₃. Mercury reacts with hot concentrated sulfuric acid to form mercuric sulfate, HgSO₄; with excess mercury, mercurous sulfate, Hg₂SO₄, is formed. Mercury reacts directly with the halogens to form mercuric salts. At elevated temperatures mercury reacts slowly with oxygen to form mercuric oxide, HgO. A mercurous oxide may be formed chemically but is unstable, decomposing to a mixture of mercury and mercuric oxide.

Natural Occurrence and Uses

Mercury occurs uncombined in nature to a limited extent. The metal is obtained commercially from cinnabar, a mercuric sulfide ore; it is easily separated by roasting the ore in air. The metal is usually purified by repeated vacuum distillation.

Mercury metal has many uses. Because of its high density, it is used in barometers and manometers. Because it has a high rate of thermal expansion that is fairly constant over a wide temperature range, it is used extensively in thermometers. Mercury is important as a liquid contact material for electric switches. It is used in mercury-vapor lamps, which emit light rich in ultraviolet radiation; various kinds of such lamps are used for street lighting, as sun lamps, and in "black lights" (see lighting). Mercury is used as an electrode in the production of chlorine and sodium hydroxide. It is also used in certain electric batteries. With some other metals mercury forms a special type of alloy called an amalgam; a special amalgam (mostly mercury, silver, and tin) is used in dentistry for filling teeth.

Mercury compounds have many uses. Calomel (mercurous chloride, Hg₂Cl₂) is used as a standard in electrochemical measurements and in medicine as a purgative. Mercuric chloride (corrosive sublimate, HgCl₂) is used as an insecticide, in rat poison, and as a disinfectant. Mercuric oxide is used in skin ointments. Mercuric sulfate is used as a catalyst in organic chemistry. Vermilion, a red pigment, is mercuric sulfide; another crystalline form of the sulfide (also used as a pigment) is black. Mercury fulminate, Hg(CNO)₂, is used as a detonator. Mercury forms many organic compounds. Mercurochrome (in 2% aqueous solution) is used in medicine as a topical antiseptic. Mercury compounds were formerly used in the treatment of syphilis.

See also mercury poisoning.

Mercury, in astronomy, nearest planet to the sun, at a mean distance of 36 million mi (58 million km); its period of revolution is 88 days. Mercury passes through phases similar to those of the moon as it completes each revolution about the sun, although the visible disk varies in size with respect to its distance from the earth. Because its greatest elongation is 28°, it is seen only for a short time after sunset or before sunrise. Since observation of Mercury is particularly unfavorable when it is near the horizon, the planet has often been studied in full daylight, with the sun's light blocked off. Mercury has the most elliptic orbit of the planets in the solar system. Its great eccentricity of orbit and its great orbital speed provided one of the important tests of Einstein's general theory of relativity. Mercury's perihelion (its closest point to the sun) is observed to advance by 43″ each century more than can be explained from planetary perturbations using Newton's theory of gravitation, yet in nearly exact agreement with the prediction of the general theory. Mercury is the smallest planet in the solar system, having a diameter of 3,031 mi (4,878 km); both Jupiter's moon Ganymede and Saturn's moon Titan are larger. Its mean density is a little less than that of the earth. Its small mass and proximity to the sun prevent it from having an appreciable atmosphere, although a slight amount of carbon dioxide has been detected. The surface of Mercury is much like that of the moon, as was shown during the Mariner 10 flybys in 1974-75 and the Messenger flybys in 2008-9. Most of its craters were formed during a period of heavy bombardment by small asteroids early in the solar system's history. The Messenger space probe also found evidence of volcanism. It was long thought that Mercury's period of rotation on its axis was identical to its period of revolution, so that the same side of the planet always faced the sun. However, radar studies in 1965 showed a period of rotation of 58.6 days. This results in periods of daylight and night of 90 earth days each, with the daylight temperatures reaching as high as 800°F; (450°C;). Night temperatures are believed to drop as low as -300°F; (-184°C;).

Mercury, in Roman religion, god of commerce and messenger of the gods; identified with the Greek Hermes. He was honored at the Mercuralia, a festival held in May and attended primarily by traders and merchants.

Harmful effects of mercury compounds. Manufacture of paints, various household items, and pesticides uses mercury; the finished product and the waste products released into air and water may contain mercury. The aquatic food chain can concentrate organic mercury compounds in fish and seafood, which, if eaten by humans, can affect the central nervous system, impairing muscle, vision, and cerebral function, leading to paralysis and sometimes death (see Minamata disease). Acute mercury poisoning causes severe digestive-tract inflammation. Mercury accumulates in the kidneys, causing uremia and death. Chronic poisoning, from occupational inhalation or skin absorption, causes metallic taste, oral inflammation, blue gum line, extremity pain and tremor, weight loss, and mental changes (depression and withdrawal). Drugs containing mercury can cause sensitivity reactions, sometimes fatal. In young children, acrodynia (pink disease) is probably caused by an organic mercury compound in house paints.

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or quicksilver

Metallic chemical element, chemical symbol Hg, atomic number 80. Mercury is the only elemental metal that is liquid at ordinary temperatures, with a freezing point of −38 °F (−39 °C) and a boiling point of 674 °F (356.9 °C). Silvery white, dense, toxic (see mercury poisoning), and a good conductor of electricity, mercury is occasionally found free in nature but usually occurs as the red sulfide ore, cinnabar (HgS). It has many uses—in dental and industrial amalgams, as a catalyst, in electrical and measuring apparatus and instruments (e.g., thermometers), as the cathode in electrolytic cells, in mercury-vapour lamps, and as a coolant and neutron absorber in nuclear power plants. Many of mercury's compounds, in which it has valence 1 or 2, are pigments, pesticides, and medicinals. It is a dangerous pollutant because it concentrates in animal tissues in increasing amounts up the food chain.

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First series of U.S. manned spaceflights (1961–63), which began about three weeks after Yury A. Gagarin became the first human in space. In May 1961 Alan B. Shepard rode the first Mercury space capsule, Freedom 7, on a 15-minute, 302-mi (486-km) suborbital flight, attaining a maximum altitude of 116 mi (186 km). The first U.S. manned flight in orbit was that of the Friendship 7, carrying John H. Glenn, Jr., in February 1962; it completed three orbits. The last Mercury flight, Faith 7, launched in May 1963, was the longest, making 22 orbits in about 34 hours.

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Mercury commonly refers to:

• Mercury (mythology), a Roman god
• Mercury (planet), the nearest planet to the Sun in the solar system
• Mercury (element), the chemical element

Mercury may also refer to:

Geography

• Mercury, Nevada, United States
• Mercury, Savoie, a village in France
• Mercury Islands, an island off the northeast coast of New Zealand
• Mercury Bay, a large V-shaped bay in New Zealand
• Mercury Boulevard, a road in Virginia, United States

Transportation

• Mercury (automobile), a marque of automobile produced by the Ford Motor Company
• Mercury (cyclecar), a United States cyclecar from 1914
• Mercury (NYC), a family of New York Central streamliner passenger trains, 1936-1958.
• Bristol Mercury, a 9-cylinder aircraft engine
• Blackburn Mercury, British aircraft from 1911
• E-6 Mercury, a United States military aircraft
• Miles Mercury, a British aircraft designed during the Second World War
• MV Celebrity Mercury, a cruise ship built in 1997
• HMS Mercury, the name of several ships of the Royal Navy
• USS Mercury, the name of several ships of the United States Navy
• Mercury, Shuttle America's callsign

Music

• Mercury (album), an album by Long-View
• Mercury (American Music Club album)
• Mercury (Madder Mortem album)
• "Mercury" (song), a song by Counting Crows
• "Mercury" (Bloc Party song)
• Mercury Records, a record label
• Mercury Prize, an annual music prize awarded for the best album from the United Kingdom
• "Mercury" , a song by Kathleen Edwards from Failer
• "Mercury, the Winged Messenger", a movement in Gustav Holst's The Planets

Comics

• Mercury (Marvel Comics), a Marvel Comics character who can turn herself into a mercurial substance
• Mercury (Amalgam Comics), a combination of the characters Impulse and Quicksilver
• Makkari (comics) or Mercury, an Eternal
• Mercury, a member of the Metal Men, a DC comics team
• Mercury, a member of Cerebro's X-Men

Computing

• Mercury Interactive, software testing tools vendor
• Mercury (programming language), a functional/logical programming language based on Prolog
• Mercury OS, a real-time operating system for embedded systems
• Ferranti Mercury, an early 1950s commercial computer
• Mercury Messenger, an WLM based instant messaging client written in Java

Sports

• Edmonton Mercurys, a 1940s and 50s intermediate ice hockey team from Canada
• Phoenix Mercury, a Women's National Basketball Association team from Arizona, United States
• Toledo Mercurys, a defunct International Hockey League franchise from Ohio, United States

Media

• Mercury (magazine), an astronomy magazine

Newspapers

• Mercury (Newport), a newspaper in Rhode Island
• Mercury (Pennsylvania), a newspaper in Pennsylvania, United States
• Clevedon Mercury, a weekly free newspaper in England
• Guelph Mercury, a Canadian newspaper
• Illawarra Mercury, a daily newspaper in Australia
• Leicester Mercury, a United Kingdom regional newspaper
• London Mercury, a list of periodicals named London Mercury published in London
• Maitland Mercury, Australia's oldest regional newspaper
• Manhattan Mercury, a newspaper in Manhattan, Kansas
• Matlock Mercury, a United Kingdom newspaper
• Mercury News, a newspaper in San Jose, CA
• Quebec Mercury, a defunct 19th Century weekly newspaper published in Quebec City, Canada
• Sherborne Mercury, a defunct newspaper from Dorset United Kingdom
• St. Arnaud Mercury, a newspaper in Victoria, Australia
• Staffordshire Mercury, a newspaper that was published in Staffordshire, England
• Sunday Mercury, a newspaper in Birmingham, United Kingdom
• The Mercury (Hobart), a newspaper in Hobart, Australia
• The Mercury (South Africa), a English language newspaper published in Durban, South Africa
• The Portland Mercury, an alternative weekly newspaper published in Oregon, United States
• The Somerset Mercury, a regional newspaper in Somerset, England
• The Weston & Somerset Mercury, a weekly paid for newspaper in Somerset, England
• Rutland And Stamford Mercury, a weekly paid-for newspaper. The oldest newspaper in England

Radio stations

• 102.7 Mercury FM, a radio station in Surrey, United Kingdom
• Hertfordshire's Mercury 96.6, an independent local radio station in England
• Mercury 96.6, a radio station in Hertfordshire, United Kingdom

Other

• Mercury (novel), a novel by Ben Bova
• Mercury (cipher machine), a British cipher machine used from the 1950s
• Mercury (satellite), the name of a series of three United States satellites
• Mercury (plant), members of the plant genus Mercurialis
• Project Mercury, an early American space program
• Operation Mercury, codename for the German invasion of Crete during World War II
• The Mercury Award, an international airline award for in-flight catering
• Conrail Mercury, an intermodal service formerly operated by Conrail
• Mercury (TV series), an Australian TV series launched in 1996

People with the name

• Daniela Mercury, Brazilian singer
• Freddie Mercury, singer of the rock group Queen
• Adam Birch, a professional wrestler with the stage name Joey Mercury
• Mercury Hayes, a former professional American football wide receiver born in 1973
• Mercury Morris, a former American football player

See also

• Mercur (disambiguation)
• Mercurius (disambiguation)
• The Mercury (disambiguation)
• Mercury 1 (disambiguation)
• Mercury 2 (disambiguation)
• Mercury 3 (disambiguation)
• Mercury 4 (disambiguation)
• Mercury chloride (disambiguation)
• Mercury House (disambiguation)
• Mercury program (disambiguation)
• Red mercury (disambiguation)