Mercury (redirected from Mercurian)

Mercury, in astronomy

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 about 3,000 mi (4,800 km); both Jupiter's moon Ganymede and Saturn's moon Titan are larger. Its mean density is comparable to 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 spacecraft flyby in 1974. Most of its craters were formed during a period of heavy bombardment by small asteroids early in the solar system's history. 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;).

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Mercury, in Roman religion

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.

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mercury, chemical element

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.

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mercury

 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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Mercury

Mercury, with winged hat and staff, classical statue; in the Uffizi, Florence

(credit: Alinari/Art Resource, New York)

In Roman religion, the god of merchants, commonly identified with the Greek messenger of the gods, Hermes. His temple on Rome's Aventine Hill was dedicated in 495 BC. The goddess Maia was identified as his mother, and the two were honoured in a festival on May 15. Mercury is sometimes depicted holding a purse, symbolic of his business functions. More often he is given the attributes of Hermes and portrayed wearing winged sandals or a winged cap and carrying a caduceus.

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Mercury

Innermost planet of the solar system. Its average distance from the Sun is about 36 million mi (58 million km), but its highly elliptical orbit carries it 7.5 million mi (12 million km) nearer to and farther from the Sun. It is the smallest major planet, having a diameter of about 3,030 mi (4,880 km) and a mass about one-eighteenth of Earth's. With the shortest period of revolution (only 88 Earth days) and the highest average orbital speed (30 mi/sec [48 km/sec]) of any planet, it is aptly named after the Roman fleet-footed messenger god. It spins very slowly, making one complete rotation relative to the stars every 59 Earth days, while its solar day (from one sunrise to the next) is 176 Earth days, owing to its revolution around the Sun. Its surface is heavily cratered. Its most impressive feature is perhaps the 800-mi (1,300-km) Caloris Basin, formed by a huge meteorite impact. Mercury also has steep cliffs that extend for hundreds of miles. The discovery of a magnetic field in its vicinity suggests it has a large iron core, which would account for a mean density almost as high as Earth's. Its atmosphere is negligible; its surface gravity, about one-third that of Earth's, holds an exceedingly tenuous layer of gases. Temperatures at its surface change dramatically, ranging from a high that can exceed 800 °F (425 °C) on the sunward side to a low of about −290 °F (−180 °C) at the end of its night.

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Mercury

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

1. a heavy silvery-white toxic liquid metallic element occurring principally in cinnabar: used in thermometers, barometers, mercury-vapour lamps, and dental amalgams. Symbol: Hg; atomic no.: 80; atomic wt.: 200.59; valency: 1 or 2; relative density: 13.546; melting pt.: --38.842?C; boiling pt.: 357?C

2. any plant of the euphorbiaceous genus Mercurialis

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Mercury¹

Roman myth the messenger of the gods

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Mercury²

the second smallest planet and the nearest to the sun. Mean distance from sun: 57.9 million km; period of revolution around sun: 88 days; period of axial rotation: 59 days; diameter and mass: 38 and 5.4 per cent that of earth respectively

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mercury [′mər·kyə·rē]

(chemistry)

A metallic element, symbol Hg, atomic number 80, atomic weight 200.59, existing at room temperature as a silvery, heavy liquid. Also known as quicksilver.

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Mercury [′mər·kyə·rē]

(astronomy)

The planet nearest to the sun; it is visible to the naked eye shortly after sunset or before sunrise when it is nearest to its greatest angular distance from the sun.

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Mercury

god of thieves. [Gk. Myth.: Wheeler, 240]

See : Thievery

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Mercury

the planet of the solar system that is closest to the sun; astronomical symbol, . Mercury is the smallest planet and has a diameter of 4,865 km (0.38 of the earth’s diameter), a mass of 3.304 X 10²³ kg (0.055 of the earth’s mass, or 1/6,025,000 of the sun’s mass), and a mean density of 5.52 g/cm³. It is a terrestrial planet.

Mercury revolves around the sun at a mean distance of 0.387 astronomical units (58 million km) in an elliptical orbit with high eccentricity (e = 0.206). At perihelion its distance from the sun is 46 million km, and at aphelion 70 million km. Mercury’s period of revolution is 88 days. Recently (in the 1960’s) it was established, by means of radar observations, that Mercury rotates about its axis in a forward direction (that is, in the same direction as its orbital motion) with a period of 58.65 days (with respect to the stars). The length of the solar day on Mercury is 176 earth days. The angular velocity of Mercury’s axial rotation is 3/2 of the orbital velocity and corresponds to the angular velocity of the planet’s motion in orbit when Mercury is at perihelion. On this basis we may assume that the rotational velocity of Mercury is due to tidal forces from the sun.

Mercury is a difficult object to observe from the earth since it is never visually further from the sun than 28°. Consequently, Mercury must always be observed against a background of morning or evening twilight, low above the horizon. Moreover, at this time the planet’s phase—that is, the angle at the planet between the directions to the sun and to the earth—is close to 90° and the observer sees only half of its disk illuminated. For this reason, only large dark patches of an unknown nature have been recorded on the surface of Mercury, and only a most general map of the planet has been compiled.

Mercury’s equator is inclined to the orbital plane by 7°. During observations at elongations, that is, the greatest angular distance from the sun, Mercury has a brightness ranging from — 0.3 to +0.6 stellar magnitude. The observed variations in brightness with phase occur in a manner similar to that of the moon. This indicates the identical nature of the irregularities of these celestial bodies. However, the reflectivity of Mercury is poorer than that of the moon and resembles that of the lunar maria. Mercury’s spherical albedo is 0.058 (visual) and 0.09 (thermal). The cross section of the disk of Mercury determined by radar in the decimeter wavelength region is only 0.06 of the geometric cross section.

Mercury may lack an atmosphere, although polarization and spectral observations indicate the presence of a thin one. Indications of the presence of carbon dioxide, CO₂, have been observed on Mercury by spectral analysis. The upper limit of the CO2 content is 4 g/cm . Nitrogen, NI, or argon, A₂, which have not been detected spectroscopically in observations from the earth, may be mixed in. The content of these gases may be several times greater than that of CO 2. In Mercury’s upper atmosphere carbon dioxide should dissociate into CO, O, and O2 on exposure to strong ultraviolet radiation from the sun. At a high kinetic temperature these atoms and molecules may easily fly into interplanetary space, since the escape velocity on Mercury is very low —4.3 km/sec.

The computed average temperature on Mercury, determined on the assumption that the planet radiates as much heat as it receives from the sun, is 505°K at the mean distance from the sun. For the point on the surface of Mercury where the sun is in the zenith—the subsolar point—the calculated temperature is 618°K and the actually measured temperature is 613°K. This temperature increases to 700°K when Mercury is at perihelion and decreases to 550°K at aphelion. The infrared radiation from the unilluminated portion of Mercury, which was measured with great difficulty, yields a nighttime temperature on Mercury of about 110°K. This may be somewhat higher but can hardly be greater than 150°K. Average (for the disk of Mercury) temperatures up to 400°K in the centimeter wavelength region and lower temperatures, 300°-200°K, in the millimeter and decimeter wavelength regions, have been observed in measurements of Mercury’s thermal flux in the radio-frequency band. But these measurements pertain to some (shallow) level beneath the surface rather than to the surface itself. This has also been confirmed by the absence of a noticeable phase effect in the measured thermal fluxes. Comparison with the fluxes measured in the infrared region of the spectrum makes it possible to derive a value of the coefficient of thermal conductivity between 1/500 and 1/700, which corresponds to similar values for the moon.

The surface of Mercury should be compared to the lunar surface with caution, since the mean density of Mercury is much greater than that of the moon. The existence of matter with a density much greater than that on the surface must be assumed in the composition of Mercury’s crust or mantle. This may be iron, either mixed with silicates or forming an independent core. The latter, however, is unlikely, since the mass of Mercury is small and radioactive decay cannot be effective, so that the iron cannot be molten. Unfortunately, none of these conclusions can be quantitatively verified, since neither the flattening of Mercury’s figure nor the planet’s rotational moment is known. Mercury has no satellites.

REFERENCE

Moroz, V. I. Fizika planet. Moscow, 1967.

D. IA. MARTYNOV

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Mercury

in ancient Roman mythology, the god of commerce and the patron of travelers. Mercury was depicted carrying a staff and wearing winged sandals and a traveler’s hat. He corresponds to Hermes in ancient Greek mythology.

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Mercury

the first American single-seat manned spacecraft for orbital flights around the earth; also, the Mercury development and launch program (1959-63). The primary task of the Mercury series was to place a manned satellite in geocentric orbit and effect its safe return to earth. It was also necessary to study the possibilities for men to work in outer space.

The launch weight of the Mercury was more than 1,800 kg (including the emergency rescue system). The cabin volume (free volume) was 1.4 cu m; height (excluding the emergency rescue system), 2.9 m; maximum diameter, 1.8 m; and minimum diameter, 0.66 m. Its lift-drag ratio was zero. The Mercury landed in water on uncontrolled parachutes. The astronaut controlled the ship by means of a manual system connected in parallel with an automatic control system. He was also able to start the retrojet and open the braking parachute manually.

In the period from Sept. 9, 1959, to Nov. 29, 1961, before the first manned Mercury spacecraft was orbited with an astronaut on board, 15 launches were made on a ballistic trajectory, three spacecraft were placed in orbit, and one satellite—the Mercury Scout, designed to test the operation of tracking stations—was launched. The flights of manned experimental spacecraft in ballistic trajectories with Redstone rockets (A. Shepard, May 5, 1961, and V. Grissom, July 21, 1961) were the most important of these. The first flight lasted 15 min; the second, 16 min. The launches of Mercury spacecraft by the Atlas D launch vehicle between Feb. 20, 1962, and May 15, 1963, are listed in Table 1.

G. A. NAZAROV

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Mercury

Hg, a chemical element in Group II of Mendeleev’s periodic system. Atomic number, 80; atomic weight, 200.59. Mercury is a silvery white heavy metal and is a liquid at room temperature. In nature, it is a mixture of seven stable isotopes with mass numbers 196 (0.2 percent), 198 (10.0 percent), 199 (16.8 percent), 200 (23.1 percent), 201 (13.2 percent), 202 (29.8 percent), and 204 (6.9 percent).

Native mercury was known in 2000 B.C. to the people of ancient India and China. Like the Greeks and Romans, they used cinnabar (native HgS) as a dye, drug, and cosmetic. The Greek physician Dioscorides in the first century A.D. heated cinnabar in an iron vessel fitted with a cover and obtained mercury vapor, which then condensed on the cool inner surface of the cover. The reaction product was called hydrargyros (Greek hydor, “water” and argyros, “silver”), that is, “liquid silver,” which is the origin of the Latin name hydrargyrum as well as of argentum vivum (quicksilver). This notion was later retained in the English “quicksilver” and the German Quecksilber. The origin of the Russian name for mercury, rtut’, has not been established.

Alchemists considered mercury a major component of all metals. The “fixation” of mercury, that is, the conversion of mercury to the solid state, was regarded as the first requirement for mercury’s conversion into gold. Solid mercury was first obtained in December 1759 by the St. Petersburg academicians I. A. Braun and M. V. Lomonosov, who managed to freeze mercury in a mixture of snow and concentrated nitric acid. In the experiments of Lomonosov, solid mercury was found to be as malleable as lead. News of the “fixation” of mercury created a sensation in the scientific world, for here was one of the most convincing proofs that mercury is similar to other metals.

In the earth’s crust, the average content of mercury, one of the extremely rare elements, is approximately 4.5 X 10^-6 percent by weight. Mercury is present in approximately the same concentration in igneous rocks. The migration of mercury in the gaseous state and in aqueous solutions plays an important role in the element’s geochemistry. In the earth’s crust, mercury is for the most part dispersed; it precipitates from hot underground waters and forms ores, in which the mercury content amounts to several percent. Chief among the 35 known mercury minerals is cinnabar (HgS).

In the biosphere, mercury is mostly scattered and is sorbed only in insignificant quantities by clays and silts. The average content of mercury in clays and shales is 4 X 10^-5 percent, and inseawater, 3 × 10^-9 percent.

Native mercury is formed through the oxidation of cinnabar into a sulfate and the subsequent decomposition of the sulfate. The decomposition can result from either a volcanic eruption or, more commonly, from a hydrothermal process, where mercury separates from aqueous solutions.

Mercury is the only metal that is a liquid at room temperature. Solid mercury forms rhombohedral crystals, where a= 3.463 angstroms (A) and c= 6.706 A. The density is 14.193 g/cm³ for solid mercury at - 38.9°Cand 13.52 g/cm³ for liquid mercury at 20°C. The atomic radius of mercury is 1.57 A, and the ionic radius of Hg²⁺ is 1.10 Å. The element’s melting point is - 38.89°C, and the boiling point is 357.25°C. The specific heat capacity of mercury at 0°C is 0.139 kilojoule per kilogram per degree Kelvin (kJ/kg-°K), or 0.03336 calorie per gram per degree centigrade (cal/g.°C); at 200°C it is 0.133 kJ/kg-°K (0.0319 cal/g-°C). The coefficient of thermal expansion is 1.826 X 10^-4 in the range 0°-100°C, and the thermal conductivity is 8.247 watts per meter per degree Kelvin (W/m•°K), or 0.0197 cal/cm•sec•°C. The resistivity of mercury at 0°C is 94.07 × 10^-8 ohm•m (94.07 X 10^-6 ohm•cm)• Mercury, which becomes a superconductor at 4.155°K, is diamagnetic, with an atomic magnetic susceptibility of - 0.19 X 10^-6 at 18°C.

The configuration of the outer electrons of the mercury atom is 5d¹⁰ 6s2, in accordance with which the cations Hg²⁺ and Hg₂²⁺ are formed in chemical reactions. The chemical reactivity of mercury is low. In dry air (or oxygen) mercury retains its luster indefinitely at room temperature. The two compounds mercury gives with oxygen are black mercurous oxide, Hg₂O, and red mercuric oxide, HgO. Mercurous oxide appears as a black layer on the surface of mercury upon the action of ozone. Mercuric oxide is formed by heating mercury in the air at a temperature of 300°–350°C or by a careful heating of the nitrate Hg(N0₃)₂ or Hg₂(NO₃)₂. Hydroxides of mercury are practically nonexistent. Upon interaction with metals wetted by mercury, amalgams are formed. Of the mercury compounds containing sulfur, HgS is the most important and is obtained by grinding mercury with sublimed sulfur at room temperature as well as by precipitation from solutions of Hg²⁺ salts with the addition of hydrogen sulfide or the sulfide of an alkali metal. With halogens (chlorine, iodine), mercury reacts upon heating to form practically nondissociating and, in most cases, poisonous compounds of the HgX₂ type. Mercury is not dissolved in hydrochloric or dilute sulfuric acid but does dissolve in aqua regia, nitric acid, and hot concentrated sulfuric acid.

Almost all Hg²⁺ salts have poor solubility in water. The nitrate Hg(N0₃)₂, however, dissolves well.

The chlorides of mercury, Hg₂Cl₂ (calomel) and HgCl₂ (corrosive sublimate), have great importance. Mercuric salts from hydrocyanic acid and thiocyanic acid are known, as is the mercury salt of fulminic acid—mercury fulminate, Hg(ONC)₂. The action of ammonia on these mercury salts leads to the formation of a number of complexes, for example, HgCl-2NH₃ (fusible white precipitate) and HgNH₂Cl (non-fusible white precipitate). The organic mercury compounds have also found use.

Mercury is obtained by roasting ores or concentrates that contain mercury in the form of cinnabar:

HgS + 0₂ = Hg + SO₂

The combustion gases pass through a dust-trapping chamber and enter a tube condenser made of stainless steel or Monel Metal; from here, liquid mercury descends into iron receivers. Purification is effected by passing the raw mercury as a thin stream through a tall vessel (1–1.5 m) of 10 percent nitric acid and by washing with water, drying, and distilling in a vacuum.

Mercury can also be obtained through a hydrometallurgical extraction from ores and concentrates. This process involves the displacement of mercury by aluminum from a solution of HgS in sodium sulfide. Methods have also been developed for obtaining mercury through the electrolysis of sulfide solutions.

Mercury is widely used in the production of such scientific instruments as barometers, thermometers, pressure gauges, vacuum pumps, normal cells, Polarographs, and capillary electrometers. It is also used in mercury-vapor lamps, switches, and rectifiers; it constitutes the liquid cathode in the production of alkali hydroxides and chlorine through electrolysis and is used as a catalyst in the synthesis of acetic acid. Mercury is used in the production of explosive substances and is employed in metallurgy for the amalgamation of gold and silver. There are a variety of uses for the element in medicine (calomel, corrosive sublimate, organic mercury compounds). Mercury is used as a pigment (cinnabar), as a herbicide and seed fungicide (organic mercury compounds), and as a component, designed to prevent the overgrowth of organisms, in the paints applied to ocean vessels. Mercury and its compounds are toxic; work with these substances therefore requires the observance of necessary safety measures.

S. A. POGODIN

Mercury in organisms. The content of mercury in organisms is approximately 10^-6 percent. The average daily intake of mercury into the human body with food is 0.02–0.05 mg. The average concentration of mercury in human blood is 0.023 micrograms per milliliter μg/ml), and in urine, 0.1–0.2 μg/ml. With the pollution of water by industrial wastes, the concentration of mercury, mainly in the form of organic compounds, in crustaceans and fish may significantly exceed the level considered safe for human consumption. Mercury ions and compounds, in binding with the mercapto groups of enzymes, can deactivate the enzymes. Upon introduction into an organism, mercury affects the assimilation and metabolism of the trace elements Cu, Zn, Cd, and Se. On the whole, the biological role of mercury in organisms has not been adequately studied.

IU. I. RAETSKAIA

Mercury poisoning. Poisoning by mercury and mercury compounds can occur in mercury mines and factories and in the production of certain measuring instruments, lamps, pharmaceutical preparations, and insecticide-fungicides.

Mercury vapors present the greatest danger, and evaporation from an uncovered surface increases with the temperature of the air. Mercury that is inhaled is introduced into the blood, where it circulates and combines with proteins. It is deposited to some extent in the liver, kidneys, spleen, and brain tissues. Its toxic effect derives from blockage of the mercapto groups in fibrous proteins and interference with the activity of the brain, in particular the hypothalamus. Mercury is eliminated from the body through the kidneys, intestines, and sweat glands.

Acute mercury poisoning is rarely encountered. Chronic poisoning manifests itself through emotional disturbances, irritability, reduction in work capacity, interference with sleep, tremors of the fingers, reduction of the olfactory sense, and headaches. One symptom of mercury poisoning is a blue-black coloring at the edge of the gums; injury to the gums (atrophy, bleeding) can lead to gingivitis and stomatitis. Poisoning from the organic compounds of mercury (diethylmercuric phosphate, diethylmercury, and ethylmercuric chloride) is characterized by concurrent injuries to the central nervous system (en-cephalopolyneuritis), cardiovascular system, stomach, liver, and kidneys.

Mercury poisoning can be treated by intravenous injections of a 20-percent hyposulfite solution (from 12 to 15 injections over the course of the treatment) and by unithiol, pharmacologic and physiotherapeutic agents to normalize the increased nervous activity, and treatment at sanatoriums (Piatigorsk, Matsesta). Preventive measures include the replacement of mercury with less harmful substances, proper methods of storage, the observance of safety rules for the handling of mercury (hermetically sealed equipment, planned division of workrooms and working surfaces, proper ventilation), personal protection, and both preliminary and periodic medical examinations.

Preparations of mercury are used in medical practice mainly because of their antiseptic and diuretic properties. Mersalyl and chlormerodrin are used as diuretics. Mercury antiseptics include corrosive sublimate, which is used in disinfecting skin, clothes, and medical instruments, and diocid, which is used in sterilizing surgical instruments. Other antiseptics are mercuric cyanide and oxycyanide, used in bathing and syringing certain inflammations, mercuric ammonium chloride, used as an ointment for skin diseases, and yellow mercuric oxide, used as an ointment for skin and eye diseases. The mercury preparations previously used in the treatment of syphilis are not used in modern medicine. A. A. KASPAROV

REFERENCES

Mel’nikov, S. M. “Rtut’.” In Kratkaia khimicheskaia entsiklopediia, vol. 4. Moscow, 1965.
Remy, H. Kurs neorganicheskoi khimii, vol. 2. Moscow, 1966. (Translated from German.)
Ripan, R., and J. Ceteanu. Neorganicheskaia khimiia. Moscow, 1972. (Translated from Rumanian.)
Nekrasov, B. V. Osnovy obshchei khimii, 2nd ed., vol. 2. Moscow, 1969.
Vrednye veshchestva v promyshlennosti, 6th ed. [part 2]. Editor in chief, N. V. Lazarev. Leningrad, 1971.
Trakhtenberg, I. M. Khronicheskoe vozdeistvie rtuti na organizm. Kiev, 1969.
Professional’nye bolezni, 3rd ed. Moscow, 1973.