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52-397: Hg is the symbol of chemical element mercury (from its Latin name hydrargyrum ). Hg , hg , HG , inHg or "Hg may also refer to: Mercury (element) Mercury is a chemical element ; it has symbol Hg and atomic number 80. 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

104-400: A half-life of 444 years, and Hg with a half-life of 46.612 days. Most of the remaining radioisotopes have half-lives that are less than a day. Hg occurs naturally in tiny traces as an intermediate decay product of U . Hg and Hg are the most often studied NMR -active nuclei, having spins of 1 ⁄ 2 and 3 ⁄ 2 respectively. Hg is

156-442: A melting point of −38.83 °C and a boiling point of 356.73 °C, both the lowest of any stable metal, although preliminary experiments on copernicium and flerovium have indicated that they have even lower boiling points. This effect is due to lanthanide contraction and relativistic contraction reducing the orbit radius of the outermost electrons, and thus weakening the metallic bonding in mercury. Upon freezing,

208-434: A mercury-aluminium amalgam when the two pure metals come into contact. Since the amalgam destroys the aluminium oxide layer which protects metallic aluminium from oxidizing in-depth (as in iron rusting ), even small amounts of mercury can seriously corrode aluminium. For this reason, mercury is not allowed aboard an aircraft under most circumstances because of the risk of it forming an amalgam with exposed aluminium parts in

260-640: A soft metal , mercury forms very stable derivatives with the heavier chalcogens . Preeminent is mercury(II) sulfide , HgS, which occurs in nature as the ore cinnabar and is the brilliant pigment vermilion . Like ZnS , HgS crystallizes in two forms , the reddish cubic form and the black zinc blende form. The latter sometimes occurs naturally as metacinnabar . Mercury(II) selenide (HgSe) and mercury(II) telluride (HgTe) are known, these as well as various derivatives, e.g. mercury cadmium telluride and mercury zinc telluride being semiconductors useful as infrared detector materials. Mercury(II) salts form

312-593: A chamber 60 feet below the 1800-year-old pyramid known as the Temple of the Feathered Serpent , the third-largest pyramid of Teotihuacan , Mexico, along with "jade statues, jaguar remains, a box filled with carved shells and rubber balls". In Lamanai , once a major city of the Maya civilization , a pool of mercury was found under a marker in a Mesoamerican ballcourt . Aristotle recounts that Daedalus made

364-459: A digital display. Some transit telescopes use a basin of mercury to form a flat and absolutely horizontal mirror, useful in determining an absolute vertical or perpendicular reference. Concave horizontal parabolic mirrors may be formed by rotating liquid mercury on a disk, the parabolic form of the liquid thus formed reflecting and focusing incident light. Such liquid-mirror telescopes are cheaper than conventional large mirror telescopes by up to

416-401: A factor of 100, but the mirror cannot be tilted and always points straight up. Liquid mercury is part of a popular secondary reference electrode (called the calomel electrode ) in electrochemistry as an alternative to the standard hydrogen electrode . The calomel electrode is used to work out the electrode potential of half cells . The triple point of mercury, −38.8344 °C, is

468-548: A fixed point used as a temperature standard for the International Temperature Scale ( ITS-90 ). In polarography , both the dropping mercury electrode and the hanging mercury drop electrode use elemental mercury. This use allows a new uncontaminated electrode to be available for each measurement or each new experiment. Oxidizing acid Oxidizing acids, being strong oxidizing agents, can often oxidize certain less reactive metals, in which

520-487: A laxative and dewormer, and it was used in teething powders for infants. The mercury-containing organohalide merbromin (sometimes sold as Mercurochrome) is still widely used but has been banned in some countries, such as the U.S. Mercury is an ingredient in dental amalgams . Thiomersal (called Thimerosal in the United States) is an organic compound used as a preservative in vaccines , although this use

572-448: A positive charge. One example is Hg 3 (AsF 6 ) 2 containing the Hg 3 cation. Mercury(II) is the most common oxidation state and is the main one in nature as well. All four mercuric halides are known and have been demonstrated to form linear coordination geometry , despite mercury's tendency to form tetrahedral molecular geometry with other ligands. This behavior

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624-459: A variety of complex derivatives with ammonia . These include Millon's base (Hg 2 N ), the one-dimensional polymer (salts of HgNH 2 ) n ), and "fusible white precipitate" or [Hg(NH 3 ) 2 ]Cl 2 . Known as Nessler's reagent , potassium tetraiodomercurate(II) ( K 2 HgI 4 ) is still occasionally used to test for ammonia owing to its tendency to form the deeply colored iodide salt of Millon's base. Mercury fulminate

676-506: A wooden statue of Aphrodite move by pouring quicksilver in its interior. In Greek mythology Daedalus gave the appearance of voice in his statues using quicksilver. The ancient Greeks used cinnabar (mercury sulfide) in ointments; the ancient Egyptians and the Romans used it in cosmetics . By 500 BC mercury was used to make amalgams (Medieval Latin amalgama , "alloy of mercury") with other metals. Alchemists thought of mercury as

728-474: Is a detonator widely used in explosives . Organic mercury compounds are historically important but are of little industrial value in the western world. Mercury(II) salts are a rare example of simple metal complexes that react directly with aromatic rings. Organomercury compounds are always divalent and usually two-coordinate and linear geometry. Unlike organocadmium and organozinc compounds, organomercury compounds do not react with water. They usually have

780-562: Is a topical antiseptic used for minor cuts and scrapes in some countries. Today, the use of mercury in medicine has greatly declined in all respects, especially in developed countries. Mercury is still used in some diuretics , although substitutes such as thiazides now exist for most therapeutic uses. In 2003, mercury compounds were found in some over-the-counter drugs , including topical antiseptics , stimulant laxatives, diaper-rash ointment , eye drops , and nasal sprays . The FDA has "inadequate data to establish general recognition of

832-409: Is also used in fluorescent lighting . 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 is a heavy, silvery-white metal that is liquid at room temperature. Compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity. It has

884-480: Is an exception, and iron flasks have traditionally been used to transport the material. Several other first row transition metals with the exception of manganese , copper and zinc are also resistant in forming amalgams. Other elements that do not readily form amalgams with mercury include platinum . Sodium amalgam is a common reducing agent in organic synthesis , and is also used in high-pressure sodium lamps. Mercury readily combines with aluminium to form

936-432: Is in decline. Although it was widely speculated that this mercury-based preservative could cause or trigger autism in children, no evidence supports any such link. Nevertheless, thiomersal has been removed from, or reduced to trace amounts in, all U.S. vaccines recommended for children 6 years of age and under, with the exception of the inactivated influenza vaccine. Merbromin (Mercurochrome), another mercury compound,

988-597: Is similar to the Ag ion. The best known mercury halide is mercury(II) chloride , an easily sublimating white solid. Mercury(II) oxide , the main oxide of mercury, arises when the metal is exposed to air for long periods at elevated temperatures. It reverts to the elements upon heating near 400 °C, as was demonstrated by Joseph Priestley in an early synthesis of pure oxygen . Hydroxides of mercury are poorly characterized, as attempted isolation studies of mercury(II) hydroxide have yielded mercury oxide instead. Being

1040-573: Is used as the ligand). Mercury(I) chloride , a colorless solid also known as calomel , is really the compound with the formula Hg 2 Cl 2 , with the connectivity Cl-Hg-Hg-Cl. It reacts with chlorine to give mercury(II) chloride , which resists further oxidation. Mercury(I) hydride , a colorless gas, has the formula HgH, containing no Hg-Hg bond; however, the gas has only ever been observed as isolated molecules. Indicative of its tendency to bond to itself, mercury forms mercury polycations , which consist of linear chains of mercury centers, capped with

1092-400: Is used in thermometers , barometers , manometers , sphygmomanometers , float valves , mercury switches , mercury relays , fluorescent lamps and other devices, although concerns about the element's toxicity have led to the phasing out of such mercury-containing instruments. It remains in use in scientific research applications and in amalgam for dental restoration in some locales. It

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1144-518: Is used in some liquid-in-glass thermometers , especially those used to measure high temperatures. A still increasing amount is used as gaseous mercury in fluorescent lamps , while most of the other applications are slowly being phased out due to health and safety regulations. In some applications, mercury is replaced with less toxic but considerably more expensive Galinstan alloy . Mercury and its compounds have been used in medicine, although they are much less common today than they once were, now that

1196-591: The First Matter from which all metals were formed. They believed that different metals could be produced by varying the quality and quantity of sulfur contained within the mercury. The purest of these was gold, and mercury was called for in attempts at the transmutation of base (or impure) metals into gold, which was the goal of many alchemists. The mines in Almadén (Spain), Monte Amiata (Italy), and Idrija (now Slovenia) dominated mercury production from

1248-478: The Neolithic Age . In China and Tibet , mercury use was thought to prolong life, heal fractures, and maintain generally good health, although it is now known that exposure to mercury vapor leads to serious adverse health effects. The first emperor of a unified China, Qín Shǐ Huáng Dì —allegedly buried in a tomb that contained rivers of flowing mercury on a model of the land he ruled, representative of

1300-546: The 1650s. Fahrenheit's mercury thermometer was based on an earlier design that used alcohol rather than mercury; the mercury thermometer was significantly more accurate than those using alcohol. From the early 21st century onwards, the use of mercury thermometers has been declining, and mercury-containing instruments have been banned in many jurisdictions following the 1998 Protocol on Heavy Metals . Modern alternatives to mercury thermometers include resistance thermometers , thermocouples , and thermistor sensors that output to

1352-548: The 1960s onward, the majority of industrial plants moved away from mercury cell processes towards diaphragm cell technologies to produce chlorine, though 11% of the chlorine made in the United States was still produced with the mercury cell method as of 2005. Thermometers containing mercury were invented in the early 18th century by Daniel Gabriel Fahrenheit , though earlier attempts at making temperature-measuring instruments filled with quicksilver had been described in

1404-537: The Greek words hydor ' water ' and argyros ' silver ' , from which its chemical symbol is derived. A heavy , silvery d-block element, mercury is the only metallic element that is known to be liquid at standard 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 . Mercury occurs in deposits throughout

1456-399: The United States and Mexico, which once produced a large proportion of the world supply, have now been completely mined out or, in the case of Slovenia ( Idrija ) and Spain ( Almadén ), shut down due to the fall of the price of mercury. Nevada 's McDermitt Mine, the last mercury mine in the United States, closed in 1992. The price of mercury has been highly volatile over the years and in 2006

1508-457: The active oxidizing agent is not H ions. For example, copper is a rather unreactive metal, and has no reaction with concentrated hydrochloric acid . However, even dilute nitric acid can oxidize copper to Cu ions, with the nitrate ions acting as the effective oxidant: Sometimes the concentration of the acid is a factor for it to be strongly oxidizing. Again, copper has no reaction with dilute sulfuric acid , but in concentrated sulfuric acid,

1560-405: The aircraft. Mercury embrittlement is the most common type of liquid metal embrittlement, as mercury is a natural component of some hydrocarbon reservoirs and will come into contact with petroleum processing equipment under normal conditions. There are seven stable isotopes of mercury, with Hg being the most abundant (29.86%). The longest-lived radioisotopes are Hg with

1612-464: The crustal mass, mercury ores can be extraordinarily concentrated considering the element's abundance in ordinary rock. The richest mercury ores contain up to 2.5% mercury by mass, and even the leanest concentrated deposits are at least 0.1% mercury (12,000 times average crustal abundance). It is found either as a native metal (rare) or in cinnabar , metacinnabar , sphalerite , corderoite , livingstonite and other minerals , with cinnabar (HgS) being

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1664-531: The dimeric cation, Hg 2 . Stable derivatives include the chloride and nitrate . In aqueous solution of a mercury(I) salt, slight disproportion of Hg 2 into Hg and Hg results in >0.5% of dissolved mercury existing as Hg . In these solutions, complexation of the Hg with addition of ligands such as cyanide causes disproportionation to go to completion, with all Hg 2 precipitating as elemental mercury and insoluble mercury(II) compounds (e.g. mercury(II) cyanide if cyanide

1716-539: The form of one of its common ores, cinnabar, is used in various traditional medicines, especially in traditional Chinese medicine . Review of its safety has found that cinnabar can lead to significant mercury intoxication when heated, consumed in overdose , or taken long term, and can have adverse effects at therapeutic doses, though effects from therapeutic doses are typically reversible. Although this form of mercury appears to be less toxic than other forms, its use in traditional Chinese medicine has not yet been justified, as

1768-471: The formula HgR 2 , which are often volatile, or HgRX, which are often solids, where R is aryl or alkyl and X is usually halide or acetate. Methylmercury , a generic term for compounds with the formula CH 3 HgX, is a dangerous family of compounds that are often found in polluted water. They arise by a process known as biomethylation . Mercury is used primarily for the manufacture of industrial chemicals or for electrical and electronic applications. It

1820-700: The historic Almaden Quicksilver Mine and created a county park on the site, after conducting extensive safety and environmental analysis of the property. All known mercury compounds exhibit one of two positive oxidation states: I and II. Experiments have failed to unequivocally demonstrate any higher oxidation states: both the claimed 1976 electrosynthesis of an unstable Hg(III) species and 2007 cryogenic isolation of HgF 4 have disputed interpretations and remain difficult (if not impossible) to reproduce. Unlike its lighter neighbors, cadmium and zinc, mercury usually forms simple stable compounds with metal-metal bonds. Most mercury(I) compounds are diamagnetic and feature

1872-490: The largest use of mercury in the late 20th century was in the mercury cell process (also called the Castner-Kellner process ) where metallic sodium is formed as an amalgam at a cathode made from mercury; this sodium is then reacted with water to produce sodium hydroxide. Many of the industrial mercury releases of the 20th century came from this process, although modern plants claim to be safe in this regard. From

1924-542: The mercury for the colonies. Mercury deposits were discovered in the New World, and more than 100,000 tons of mercury were mined from the region of Huancavelica , Peru, over the course of three centuries following the discovery of deposits there in 1563. The patio process and later pan amalgamation process continued to create great demand for mercury to treat silver ores until the late 19th century. Former mines in Italy,

1976-569: The mercury required for CFL bulb manufacture. Environmental dangers have been a concern, particularly in the southern cities of Foshan and Guangzhou , and in Guizhou province in the southwest. Abandoned mercury mine processing sites often contain very hazardous waste piles of roasted cinnabar calcines . Water run-off from such sites is a recognized source of ecological damage. Former mercury mines may be suited for constructive re-use; for example, in 1976 Santa Clara County, California purchased

2028-606: The mining of cinnabar and refining for mercury are hazardous and historic causes of mercury poisoning. In China, prison labor was used by a private mining company as recently as the 1950s to develop new cinnabar mines. Thousands of prisoners were used by the Luo Xi mining company to establish new tunnels. Worker health in functioning mines is at high risk. A newspaper claimed that an unidentified European Union directive calling for energy-efficient lightbulbs to be made mandatory by 2012 encouraged China to re-open cinnabar mines to obtain

2080-501: The modern chemical symbol for mercury. It is an abbreviation of hydrargyrum , a romanized form of the ancient Greek name for mercury, ὑδράργυρος ( hydrargyros ). Hydrargyros is a Greek compound word meaning ' water-silver ' , from ὑδρ - ( hydr -), the root of ὕδωρ ( hydor ) ' water ' , and ἄργυρος ( argyros ) ' silver ' . Like the English name quicksilver ( ' living-silver ' ), this name

2132-691: The most common ore. Mercury ores often occur in hot springs or other volcanic regions. Beginning in 1558, with the invention of the patio process to extract silver from ore using mercury, mercury became an essential resource in the economy of Spain and its American colonies. Mercury was used to extract silver from the lucrative mines in New Spain and Peru . Initially, the Spanish Crown's mines in Almadén in Southern Spain supplied all

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2184-461: The opening of the mine in Almadén 2500 years ago, until new deposits were found at the end of the 19th century. Mercury is an extremely rare element in Earth's crust ; it has an average crustal abundance by mass of only 0.08 parts per million (ppm) and is the 66th most abundant element in the Earth's crust. Because it does not blend geochemically with those elements that constitute the majority of

2236-468: The planet became one of the alchemical symbols for the metal, and Mercury became an alternative name for the metal. Mercury is the only metal for which the alchemical planetary name survives, as it was decided it was preferable to quicksilver as a chemical name. Mercury was found in Egyptian tombs that date from 1500 BC; cinnabar , the most common natural source of mercury, has been in use since

2288-483: The rivers of China—was reportedly killed by drinking a mercury and powdered jade mixture formulated by Qin alchemists intended as an elixir of immortality. Khumarawayh ibn Ahmad ibn Tulun , the second Tulunid ruler of Egypt (r. 884–896), known for his extravagance and profligacy , reportedly built a basin filled with mercury, on which he would lie on top of air-filled cushions and be rocked to sleep. In November 2014 "large quantities" of mercury were discovered in

2340-423: The safety and effectiveness" of the mercury ingredients in these products. Chlorine is produced from sodium chloride (common salt, NaCl) using electrolysis to separate metallic sodium from chlorine gas. Usually salt is dissolved in water to produce a brine. By-products of any such chloralkali process are hydrogen (H 2 ) and sodium hydroxide (NaOH), which is commonly called caustic soda or lye . By far

2392-409: The symptoms of its toxicity were confused with those of the syphilis it was believed to treat. It is also used as a disinfectant. Blue mass , a pill or syrup in which mercury is the main ingredient, was prescribed throughout the 19th century for numerous conditions including constipation, depression, child-bearing and toothaches. In the early 20th century, mercury was administered to children yearly as

2444-418: The therapeutic basis for the use of cinnabar is not clear. Mercury(I) chloride (also known as calomel or mercurous chloride) has been used in traditional medicine as a diuretic , topical disinfectant , and laxative . Mercury(II) chloride (also known as mercuric chloride or corrosive sublimate) was once used to treat syphilis (along with other mercury compounds), although it is so toxic that sometimes

2496-415: The toxic effects of mercury and its compounds are more widely understood. An example of the early therapeutic application of mercury was published in 1787 by James Lind . The first edition of The Merck Manuals (1899) featured many then-medically relevant mercuric compounds, such as mercury-ammonium chloride , yellow mercury proto-iodide , calomel , and mercuric chloride , among others. Mercury in

2548-941: The volume of mercury decreases by 3.59% and its density changes from 13.69 g/cm when liquid to 14.184 g/cm when solid. The coefficient of volume expansion is 181.59 × 10 at 0 °C, 181.71 × 10 at 20 °C and 182.50 × 10 at 100 °C (per °C). Solid mercury is malleable and ductile, and can be cut with a knife. Table of thermal and physical properties of liquid mercury: Mercury does not react with most acids, such as dilute sulfuric acid , although oxidizing acids such as concentrated sulfuric acid and nitric acid or aqua regia dissolve it to give sulfate , nitrate , and chloride . Like silver, mercury reacts with atmospheric hydrogen sulfide . Mercury reacts with solid sulfur flakes, which are used in mercury spill kits to absorb mercury (spill kits also use activated carbon and powdered zinc). Mercury dissolves many metals such as gold and silver to form amalgams . Iron

2600-507: The world mostly as cinnabar ( mercuric sulfide ). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Exposure to mercury and mercury-containing organic compounds is toxic to the nervous system , immune system and kidneys of humans and other animals; mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury ) either directly or through mechanisms of biomagnification . Mercury

2652-400: Was $ 650 per 76-pound (34.46 kg) flask . Mercury is extracted by heating cinnabar in a current of air and condensing the vapor. The equation for this extraction is: In 2020, China was the top producer of mercury, providing 88% of the world output (2200 out of 2500 tonnes), followed by Tajikistan (178 t), Russia (50 t) and Mexico (32 t). Because of the high toxicity of mercury, both

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2704-500: Was due to mercury's liquid and shiny properties. The modern English name mercury comes from the planet Mercury . In medieval alchemy , the seven known metals—quicksilver, gold , silver , copper , iron , lead , and tin —were associated with the seven planets. Quicksilver was associated with the fastest planet, which had been named after the Roman god Mercury , who was associated with speed and mobility. The astrological symbol for

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