Mercury (IPA: [ˈmɜːkjəˌɹi]), also called quicksilver, is a chemical element in the periodic table that has the symbol Hg (Latinized Greek: hydrargyrum, meaning watery or liquid silver) and atomic number 80. A heavy, silvery transition metal, mercury is one of five elements that are liquid at or near room temperature and pressure.[1] The others are the metals caesium, francium, and ga
llium, and the non-metal bromine.
Mercury is used in thermometers, barometers and other scientific apparatus, though concerns about the element's toxicity have led to mercury thermometers being largely phased out in clinical environments in favour of alcohol-filled, digital or thermistor-based instruments. It remains in use in a number of other ways in scientific and scientific research applications, and in dental amalgam. Mercury is mostly obtained by reduction from the mineral, cinnabar.
Mercury occurs in deposits throughout the world and it is harmless in an insoluble form, such as mercuric sulfide, but it is poisonous in soluble forms such as mercuric chloride .
llium, and the non-metal bromine.Mercury is used in thermometers, barometers and other scientific apparatus, though concerns about the element's toxicity have led to mercury thermometers being largely phased out in clinical environments in favour of alcohol-filled, digital or thermistor-based instruments. It remains in use in a number of other ways in scientific and scientific research applications, and in dental amalgam. Mercury is mostly obtained by reduction from the mineral, cinnabar.
Mercury occurs in deposits throughout the world and it is harmless in an insoluble form, such as mercuric sulfide, but it is poisonous in soluble forms such as mercuric chloride .
History
Mercury was known to the ancient Chinese and Hindus, and was found in Egyptian tombs that date from 1500 BC.[citation needed] In China, India, and Tibet, mercury use was thought to prolong life, heal fractures, and maintain generally good health. China's first emperor, Qin Shi Huang Di — said to have been buried in a tomb that containe
d rivers of flowing mercury, representative of the rivers of China — was driven insane and killed by mercury pills intended to give him eternal life. The ancient Greeks used mercury in ointments and the Romans used it in cosmetics. By 500 BC mercury was used to make amalgams with other metals. The Indian word for alchemy is Rasavātam which means ‘the way of mercury’. Alchemists often thought of mercury as the First Matter from which all metals were formed. Different metals could be produced by varying the quality and quantity of sulfur contained within the mercury. An ability to transform mercury into any metal resulted from the essentially mercurial quality of all metals. The purest of these was gold, and mercury was required for the transmutation of base (or impure) metals into gold as was the goal of many alchemists.Hg is the modern chemical symbol for mercury. It comes from hydrargyrum, a Latinized form of the Greek word `Υδραργυρος (hydrargyros), which is a compound word meaning 'water' and 'silver' — since it is liquid, like water, and yet has a silvery metallic sheen. The element was named after the Roman god Mercury, known for speed and mobility. It is associated with the planet Mercury. The astrological symbol for the planet is also one of the alchemical symbols for the metal (above left). Mercury is the only metal for which the alchemical planetary name became the common name.
Hat making
From the mid-18th to the mid-19th centuries, a process called "carroting" was used in the making of felt hats. Animal skins were rinsed in an orange solution of the mercury compound mercuric nit
rate, Hg(NO3)2·2H2O.[2] This process separated the fur from the pelt and matted it together. This solution and the vapors it produced were highly toxic. Its use resulted in widespread cases of mercury poisoning among hatters. Symptoms included tremors, emotional lability, insomnia, dementia and hallucinations. The United States Public Health Service banned the use of mercury in the felt industry in December 1941. The psychological symptoms associated with mercury poisoning may have inspired the phrase "mad as a hatter"; see the hatter article on the origin of the phrase. Lewis Carroll's "Mad Hatter" in his book Alice's Adventures in Wonderland was based on this fact.Production of chlorine and caustic soda
Chlorine is produced from Sodium chloride (common salt, NaCl) using electrolysis to separate the metallic sodium from the chlorine gas. Usually the salt is dissolved in water to produce a brine. By-products of any such chloralkali process
are caustic soda (sodium hydroxide (NaOH)) and hydrogen (H2). By far the largest use of mercury[3][4] in the late 1900s 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.[5] Many of the industrial mercury releases of the 1900s came from this process, although modern plants claimed to be safe in this regard. [4] After about 1985, all new chloralkali production facilities that were built in the United States used either membrane cell or diaphragm cell technologies to produce chlorine.
are caustic soda (sodium hydroxide (NaOH)) and hydrogen (H2). By far the largest use of mercury[3][4] in the late 1900s 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.[5] Many of the industrial mercury releases of the 1900s came from this process, although modern plants claimed to be safe in this regard. [4] After about 1985, all new chloralkali production facilities that were built in the United States used either membrane cell or diaphragm cell technologies to produce chlorine.Dentistry
Elemental mercury is the main ingredient in dental amalgams. Controversy over the health effects from the use of mercury amalgams began shortly after its introduction into the western world, nearly 200 years ago. In 1845, The American Society of Dental Sur
geons, concerned about mercury poisoning, asked its members to sign a pledge that they would not use amalgam. The ASDS disbanded in 1865. The American Dental Association formed three years after and currently takes the position that "amalgam is a valuable, viable and safe choice for dental patients,"[6] In 1993, the United States Public Health Service reported that "amalgam fillings release small amounts of mercury vapor," but in such a small amount that it "has not been shown to cause any … adverse health effects". This position is not shared by all governments and there is an ongoing dental amalgam controversy. A recent review by an FDA-appointed advisory panel rejected, by a margin of 13-7, the current FDA report on amalgam safety[citation needed], stating the report's conclusions were unreasonable given the quantity and quality of information currently available. Panelists said remaining uncertainties about the risk of so-called silver fillings demanded further research; in particular, on the effects of mercury-laden fillings on children and the fetuses of pregnant women with fillings, and the release of mercury vapor on insertion and removal of mercury fillings.[citation needed]
geons, concerned about mercury poisoning, asked its members to sign a pledge that they would not use amalgam. The ASDS disbanded in 1865. The American Dental Association formed three years after and currently takes the position that "amalgam is a valuable, viable and safe choice for dental patients,"[6] In 1993, the United States Public Health Service reported that "amalgam fillings release small amounts of mercury vapor," but in such a small amount that it "has not been shown to cause any … adverse health effects". This position is not shared by all governments and there is an ongoing dental amalgam controversy. A recent review by an FDA-appointed advisory panel rejected, by a margin of 13-7, the current FDA report on amalgam safety[citation needed], stating the report's conclusions were unreasonable given the quantity and quality of information currently available. Panelists said remaining uncertainties about the risk of so-called silver fillings demanded further research; in particular, on the effects of mercury-laden fillings on children and the fetuses of pregnant women with fillings, and the release of mercury vapor on insertion and removal of mercury fillings.[citation needed]medicine
Mercury and its compounds have been used in medicine for centuries, although they are much less common today than they once were, now that the toxic effects of mercury and its compounds are more widely understood.
Mercury(I) chloride (also known as calomel or mercurous chloride) has traditionally been used 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 the symptoms of its toxicity were confused with those of the syphilis it was believed to treat.[7] It was also used as a disinfectant. Blue mass, a pill or syrup in which mercury is the main ingredient, was prescribed throughout the 1800s for numerous conditions including constipation, depression, child-bearing and toothaches.[8] In the early 20th century, mercury was administered to children yearly as a laxative and dewormer, and it was used in teething powders for infants. The mercury containing organohalide Mercurochrome is still widely used but has been banned in some countries such as the U.S.
Since the 1930s some vaccines have contained the preservative thiomersal, which is metabolized or degraded to ethyl mercury. Although it was widely speculated that this mercury-based preservative can cause or trigger autism in children, scientific studies showed no evidence supporting any such link.[9] 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 inactivated influenza vaccine.[10]
Mercury in the form of one of its common ores, cinnabar, remains an important component of Chinese, Tibetan, and Ayurvedic medicine. As problems may arise when these medicines are exported to countries that prohibit the use of mercury in medicines, in recent times, less toxic substitutes have been devised.
Today, the use of mercury in medicine has greatly declined in all respects, especially in developed countries. Thermometers and sphygmomanometers containing mercury were invented in the early 18th and late 19th centuries, respectively. In the early 21st century, their use is declining and has been banned in some countries, states and medical institutions. In 2002, the U.S. Senate passed legislation to phase out the sale of non-prescription mercury thermometers. In 2003, Washington and Maine became the first states to ban mercury blood pressure devices.[11] Mercury compounds are found in some over-the-counter drugs, including topical antiseptics, stimulant laxatives, diaper-rash ointment, eye drops, and nasal sprays. The FDA (FDA) has “inadequate data to establish general recognition of the safety and effectiveness,” of the mercury ingredients in these products.[12] Mercury is still used in some diuretics, although substitutes now exist for most therapeutic uses.
Mercury(I) chloride (also known as calomel or mercurous chloride) has traditionally been used 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 the symptoms of its toxicity were confused with those of the syphilis it was believed to treat.[7] It was also used as a disinfectant. Blue mass, a pill or syrup in which mercury is the main ingredient, was prescribed throughout the 1800s for numerous conditions including constipation, depression, child-bearing and toothaches.[8] In the early 20th century, mercury was administered to children yearly as a laxative and dewormer, and it was used in teething powders for infants. The mercury containing organohalide Mercurochrome is still widely used but has been banned in some countries such as the U.S.
Since the 1930s some vaccines have contained the preservative thiomersal, which is metabolized or degraded to ethyl mercury. Although it was widely speculated that this mercury-based preservative can cause or trigger autism in children, scientific studies showed no evidence supporting any such link.[9] 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 inactivated influenza vaccine.[10]
Mercury in the form of one of its common ores, cinnabar, remains an important component of Chinese, Tibetan, and Ayurvedic medicine. As problems may arise when these medicines are exported to countries that prohibit the use of mercury in medicines, in recent times, less toxic substitutes have been devised.
Today, the use of mercury in medicine has greatly declined in all respects, especially in developed countries. Thermometers and sphygmomanometers containing mercury were invented in the early 18th and late 19th centuries, respectively. In the early 21st century, their use is declining and has been banned in some countries, states and medical institutions. In 2002, the U.S. Senate passed legislation to phase out the sale of non-prescription mercury thermometers. In 2003, Washington and Maine became the first states to ban mercury blood pressure devices.[11] Mercury compounds are found in some over-the-counter drugs, including topical antiseptics, stimulant laxatives, diaper-rash ointment, eye drops, and nasal sprays. The FDA (FDA) has “inadequate data to establish general recognition of the safety and effectiveness,” of the mercury ingredients in these products.[12] Mercury is still used in some diuretics, although substitutes now exist for most therapeutic uses.
the environment
occurrenceMercury is an extremely rare element in the earth's crust, having an average crustal abundance by mass of only 0.08 parts per million. However, because it does not blend geochemically with those elements that comprise the majority of 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, corderoite, livingstonite and other minerals, with cinnabar (HgS) being the most common ore. Mercury ores usually occur in very young orogenic belts where rock of high density are forced to the crust of the Earth, often in hot springs or other volcanic regions.
Over 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; mercury from Huancavelica was crucial in the production of silver in colonial Spanish America. Many former ores in Italy, Slovenia, the United States and Mexico which once produced a large proportion of the world's supply have now been completely mined out. The metal is extracted by heating cinnabar in a current of air and condensing the vapor.
In 2005, China was the top producer of mercury with almost two-thirds global share followed by Kyrgyzstan, reports the British Geological Survey.[citation needed] Several other countries are believed to have unrecorded production of mercury from copper electrowinning processes and by recovery from effluents.
Due to minimal surface disruption, mercury mines lend themselves to constructive re-use. For example, in 1976 Santa Clara County, California purchased the historic Almaden Quicksilver Mine and proceeded to create a county park on the site, after conducting extensive safety and environmental analysis of the property.
It is found either as a native metal (rare) or in cinnabar, corderoite, livingstonite and other minerals, with cinnabar (HgS) being the most common ore. Mercury ores usually occur in very young orogenic belts where rock of high density are forced to the crust of the Earth, often in hot springs or other volcanic regions.
Over 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; mercury from Huancavelica was crucial in the production of silver in colonial Spanish America. Many former ores in Italy, Slovenia, the United States and Mexico which once produced a large proportion of the world's supply have now been completely mined out. The metal is extracted by heating cinnabar in a current of air and condensing the vapor.
In 2005, China was the top producer of mercury with almost two-thirds global share followed by Kyrgyzstan, reports the British Geological Survey.[citation needed] Several other countries are believed to have unrecorded production of mercury from copper electrowinning processes and by recovery from effluents.
Due to minimal surface disruption, mercury mines lend themselves to constructive re-use. For example, in 1976 Santa Clara County, California purchased the historic Almaden Quicksilver Mine and proceeded to create a county park on the site, after conducting extensive safety and environmental analysis of the property.
