Mercury , also

Zn(C2Hs)2 -E 2H2O Zn(OH)2 -E (Cadmium and mercury also form alkyls.)... 

Boiling point is given at atmospheric pressure (760 mm of mercury or 101 325 Pa) unless otherwise indicated thus 82 indicates that the boiling point is 82°C when the pressure is 15 mm of mercury. Also, subl 550 indicates that the compound sublimes at 550°C. Occasionally decomposition products are mentioned. 

The biochemical basis for the toxicity of mercury and mercury compounds results from its ability to form covalent bonds readily with sulfur. Prior to reaction with sulfur, however, the mercury must be metabolized to the divalent cation. When the sulfur is in the form of a sulfhydryl (— SH) group, divalent mercury replaces the hydrogen atom to form mercaptides, X—Hg— SR and Hg(SR)2, where X is an electronegative radical and R is protein (36). Sulfhydryl compounds are called mercaptans because of their ability to capture mercury. Even in low concentrations divalent mercury is capable of inactivating sulfhydryl enzymes and thus causes interference with cellular metaboHsm and function (31—34). Mercury also combines with other ligands of physiological importance such as phosphoryl, carboxyl, amide, and amine groups. It is unclear whether these latter interactions contribute to its toxicity (31,36). 

Most inorganic mercury compounds have very low vapor pressures, and generally do not contribute to high mercury vapor readings. MetaUic mercury is the most potent and troublesome in this respect. Organic mercurials also contribute to mercury vapor readings, possibly by virtue of the presence of extremely small amounts of metallic mercury present as an impurity. 

Density and Specific Gravity. Water has a density, mass per unit volume, of about 62.4 lb/fU (1.000 g/cc) at 0°C, whereas mercury, also a Hquid, has a density of about 842 lb/ft (13.5 g/cc) at the same temperature. AH things being equal, greater densities mean thicker required tank sheU thicknesses. 

Precipitation is often applied to the removal of most metals from wastewater including zinc, cadmium, chromium, copper, fluoride, lead, manganese, and mercury. Also, certain anionic species can be removed by precipitation, such as phosphate, sulfate, and fluoride. Note that in some cases, organic compounds may form organometallic complexes with metals, which could inhibit precipitation. Cyanide and other ions in the wastewater may also complex with metals, making treatment by precipitation less efficient. A cutaway view of a rapid sand filter that is most often used in a municipal treatment plant is illustrated in Figure 4. The design features of this filter have been relied upon for more than 60 years in municipal applications. 

Zinc and cadmium tarnish quickly in moist air and combine with oxygen, sulfur, phosphorus and the halogens on being heated. Mercury also reacts with these elements, except phosphorus and its reaction with oxygen was of considerable practical importance in the early work of J. Priestley and A. L. Lavoisier on oxygen (p. 601). The reaction only becomes appreciable at temperatures of about 350° C, but above about 400°C HgO decomposes back into the elements. 

Most substances expand when heated and contract when cooled, but liquid mercury shows an especially large variation of volume with temperature. That is why it is so often used in thermometers and barometers. Mercury also mixes with a number of metals to form alloys called amalgams. Amalgam is a special name given to alloys of mercury. With silver it forms a silver amalgam, which quickly hardens. This is the silver filling used by dentists. 

The chlorodifluorophosphine prepared in this manner has a vapor pressure of 312.0 mm. at —63.6° (chloroform slush). The infrared spectrum of the vapor shows absorptions at the following frequencies 864.5 (s), 853.5 (vs), 543.7 (s), and 412.5 (m) cm.-1 in the 4000 to 200 cm.-1 region. Disproportionation of the liquid is fairly rapid contact of the vapor with mercury also appears to hasten disproportionation. Thus chlorodifluorophosphine is best prepared just prior to use. It may be stored at —196°. 

Following a single dose of mercuric chloride to rats, mercury also tended to accumulate with time after injection in the Iysosome-peroxisome group of particles [47]. This accumulation may represent a detoxication process [48]. 

The critical part of any sampling task is to obtain a sample that represents the bulk system as well as possible. As stated in Chapter 1, the sample must possess all the characteristics of the entire bulk system with respect to the analyte and the analyte concentration in the system. In other words, it must be a representative sample—it must truly represent the bulk system. Whatever concentration level is found for a given component of a sample is also then taken to be the concentration level in the entire system. For example, in order to analyze the water in a lake for mercury, a bottle is filled with the water and is then taken into the laboratory for analysis. If the mercury level in this sample is determined to be 12 parts per million (ppm), then, assuming the sample is representative of the entire lake, the entire lake is assumed to be 12 ppm in mercury also. 

Although the description fulminating is not used and thus confusion with the fulminate not caused, mercury also forms explosive compounds of similar nature. The nitride (ibid.) is the most common and can be formed from the metal and ammonia in some circumstances, causing accidents where mercury manometers are used with ammonia. Halo-hydroxy- and oxy-nitrides can also be involved [3], See METAL FULMINATES, GOLD COMPOUNDS, A-METAL DERIVATIVES, PRECIOUS METAL DERIVATIVES, SILVER COMPOUNDS... 

Most cases of mercury poisoning led to handicap, chronic disease, or death. The most frequent symptoms include numbness of limbs, lips and tongue, speech abnormalities, limb function disorders, visual acuity disorders, deafness, and muscular atrophy. Insomnia, hyperactivity, and coma have also been reported. Methylmercury penetrates the blood-brain barrier and causes central nervous system injuries. Mercury also has a teratogenic effect, leading to congenital abnormalities or congenital Minamata disease. 

Inukai et al. [29] have carried out UPD of mercury also on Au(lll) and have investigated this process by in situ STM in sulfuric and perchloric acid solutions. 

By the end of the seventeenth century, the old traditional elements from Aristotle had been either abandoned by the new Paracelsian iatrochymists or absorbed under new terminology. Paracelsus tria prima of mercury, SULPHUR, and salt became the new set of elements or principles, each more narrowly focused on a single property than had been the four elements of Aristotle. Yet the tria prima clearly derived from the older tradition. Salt assumed the role of the Aristotelian earth, while sulphur took that of FIRE. The mercury of Paracelsus rather absorbed the characteristics of both AIR and water, becoming the carrier of all spiritual, i.e., volatile qualities of the products of fire analysis. Mercury also carried the basic metallic properties from the mercury/sulphur theory of metals brought to the Latin West from Arabic alchemy. 

Chlorides of iron, zinc, cadmium and mercury also behave in a similar manner. 

There is further analogy with yet "extra concern for toxic chemicals that may also persist in the environment and be transported great distances from their point of entry into the environment. Here the unifying general notion is that unsuspecting individuals are placed at risk, and are thus less able to defend than are the perpetrators. Mercury is a classic example of such a chemical. Mercury is extremely toxic to the CN S. Fetuses, infants, and toddlers are especially sensitive and susceptible to the neurotoxic properties of mercury. Mercury also persists in the environment, and is known to bioaccumulate in the food web and biomagnify up the food chain. 

A. J. Balard found mercury immediately decomposes hypochlorous acid without the disengagement of any gas, but mercury oxychloride is formed. P. Grouvelle reported previously that when chlorine acts on mercuric oxide suspended in water, mercury oxychloride, very slightly soluble in cold water, is formed. L. J. Thenard found that the liquid contained both chloride and chlorate of mercury, also in soln. A. J. Balard, however, believed that these bodies are formed consecutively, and that their existence was preceded by that of a mercuric hypochlorite, as takes place with the salts of silver, and, as previously indicated, he prepared hypochlorous acid by the action of chlorine on mercuric oxide suspended in water. No mercury hypobromite has yet been isolated. There is a possible formation of mercury hypoiodite, or more probably of hypoiodous acid, when iodine is shaken up with... 

Sulfur tetrafluoride is thermally stable up to 600 °C. Within the temperature range 600-1000 C, less than 1 % undergoes disproportionation to sulfur hexafluoride and sulfur.24 Most of the common construction metals, such as copper, nickel and steel, are resistant to sulfur tetrafluoride. Mercury also does not react with sulfur tetrafluoride.3 The recommended construction material for work with sulfur tetrafluoride is Hastelloy or stainless steel and, at low pressure,... 

Iodides, bromides, and selenidesof mercury also occur, but rarely. The iodide has been met with in Mexico, associated with the selcnide, A specimen of the bromide Dr. Dalzell found to contain, besides bromine, traces of Iodine, selenium, and sulphur. Bost5 has described the aelenide as composed of selenium 6-49, sulphur 10-30, and mercury 81-33. 

Group 12 In order of increasing atomic number, ihese are zinc, cadmium, and mercury, The eleiiieuls of this group are characterized by the presence ol two electrons in an outer shell Although mercury also has a valence of I -l, all of the elements in this, group have a 7+ valence in common. 

INCH OF MERCURY (inHg). A unit of pressure. One inch of mercury equals 3,386.4 newtons per square miter. (An inch of mercury also equals (1) 0.03342 atmosphere (2) 1.133 feet of water (3) 345.3 kilograms/square meter, (4) 70.73 pounds/square foot, or (5) 0.4912 pounds/square inch. 

The millimeter of mercury, also called a ton after the seventeenth-century Italian scientist Evangelista Torricelli (1608-1647), is based on atmospheric pressure... 

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