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 (/haɪˈdrɑːrdʒərəm/ hy-DRAR-jər-əm) from the Greek words hydor (water) and argyros (silver).[8] 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.[a]
Mercury
shiny, silvery liquid
$_$_$DEEZ_NUTS#1__answer--1DEEZ_NUTS$_$_$
80
[Xe] 4f14 5d10 6s2
2, 8, 18, 32, 18, 2
234.3210 K (−38.8290 °C, −37.8922 °F)
629.88 K (356.73 °C, 674.11 °F)
13.546 g/cm3 [3]
234.3156 K, 1.65×10−7 kPa
1750 K, 172.00 MPa
2.29 kJ/mol
59.11 kJ/mol
27.983 J/(mol·K)
−2 , +1, +2 (a mildly basic oxide)
Pauling scale: 2.00
- 1st: 1007.1 kJ/mol
- 2nd: 1810 kJ/mol
- 3rd: 3300 kJ/mol
empirical: 151 pm
132±5 pm
155 pm
rhombohedral (hR1)
60.4 µm/(m⋅K) (at 25 °C)
8.30 W/(m⋅K)
961 nΩ⋅m (at 25 °C)
diamagnetic[5]
−33.44×10−6 cm3/mol (293 K)[6]
liquid: 1451.4 m/s (at 20 °C)
7439-97-6
Ancient Egyptians (before 1500 BCE)
"Hg": from its Latin name hydrargyrum, itself from Greek hydrárgyros, 'water-silver'
Mercury occurs in deposits throughout 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 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.[9] It remains in use in scientific research applications and in amalgam for dental restoration in some locales. It 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.
History
Mercury was found in Egyptian tombs that date from 1500 BC;[28] cinnabar, the most common natural source of mercury, has been in use since the Neolithic Age.[29]
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.[30] 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 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.[31][32] 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.[33]
In November 2014 "large quantities" of mercury were discovered in 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".[34]
Aristotle recounts that Daedalus made a wooden statue of Venus move by pouring quicksilver in its interior.[35] 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. In Lamanai, once a major city of the Maya civilization, a pool of mercury was found under a marker in a Mesoamerican ballcourt.[36][37] By 500 BC mercury was used to make amalgams (Medieval Latin amalgama, "alloy of mercury") with other metals.[38]
Alchemists thought of mercury as 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.[26]
The mines in Almadén (Spain), Monte Amiata (Italy), and Idrija (now Slovenia) dominated mercury production from the opening of the mine in Almadén 2500 years ago, until new deposits were found at the end of the 19th century.[39]
The deep violet glow of a mercury vapor discharge in a germicidal lamp, whose spectrum is rich in invisible ultraviolet radiation.
Skin tanner containing a low-pressure mercury vapor lamp and two infrared lamps, which act both as light source and electrical ballast
Assorted types of fluorescent lamps.
The miniaturized Deep Space Atomic Clock is a linear ion-trap-based mercury ion clock, designed for precise and real-time radio navigation in deep space.
Regulations
International
140 countries agreed in the Minamata Convention on Mercury by the United Nations Environment Programme (UNEP) to prevent mercury vapor emissions.[162] The convention was signed on 10 October 2013.[163]
United States
In the United States, the Environmental Protection Agency is charged with regulating and managing mercury contamination. Several laws give the EPA this authority, including the Clean Air Act, the Clean Water Act, the Resource Conservation and Recovery Act, and the Safe Drinking Water Act. Additionally, the Mercury-Containing and Rechargeable Battery Management Act, passed in 1996, phases out the use of mercury in batteries, and provides for the efficient and cost-effective disposal of many types of used batteries.[164] North America contributed approximately 11% of the total global anthropogenic mercury emissions in 1995.[165]
The United States Clean Air Act, passed in 1990, put mercury on a list of toxic pollutants that need to be controlled to the greatest possible extent. Thus, industries that release high concentrations of mercury into the environment agreed to install maximum achievable control technologies (MACT). In March 2005, the EPA promulgated a regulation[166] that added power plants to the list of sources that should be controlled and instituted a national cap and trade system. States were given until November 2006 to impose stricter controls, but after a legal challenge from several states, the regulations were struck down by a federal appeals court on 8 February 2008. The rule was deemed not sufficient to protect the health of persons living near coal-fired power plants, given the negative effects documented in the EPA Study Report to Congress of 1998.[167] However newer data published in 2015 showed that after introduction of the stricter controls mercury declined sharply, indicating that the Clean Air Act had its intended impact.[168]
The EPA announced new rules for coal-fired power plants on 22 December 2011.[169] Cement kilns that burn hazardous waste are held to a looser standard than are standard hazardous waste incinerators in the United States, and as a result are a disproportionate source of mercury pollution.[170]
European Union
In the European Union, the directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (see RoHS) bans mercury from certain electrical and electronic products, and limits the amount of mercury in other products to less than 1000 ppm.[171] There are restrictions for mercury concentration in packaging (the limit is 100 ppm for sum of mercury, lead, hexavalent chromium and cadmium) and batteries (the limit is 5 ppm).[172] In July 2007, the European Union also banned mercury in non-electrical measuring devices, such as thermometers and barometers. The ban applies to new devices only, and contains exemptions for the health care sector and a two-year grace period for manufacturers of barometers.[173]
Norway enacted a total ban on the use of mercury in the manufacturing and import/export of mercury products, effective 1 January 2008.[174] In 2002, several lakes in Norway were found to have a poor state of mercury pollution, with an excess of 1 μg/g of mercury in their sediment.[175] In 2008, Norway's Minister of Environment Development Erik Solheim said: "Mercury is among the most dangerous environmental toxins. Satisfactory alternatives to Hg in products are available, and it is therefore fitting to induce a ban."[176] Products containing mercury were banned in Sweden in 2009,[177][178] while elemental mercury has been banned from manufacture and use in all but a few applications (such as certain energy-saving light sources and amalgam dental fillings) in Denmark since 2008.[179]