Title: Mercury
CAS Registry Number: 7439-97-6
Additional Names: Hydrargyrum; liquid silver; quicksilver
Literature References: Hg; at. wt 200.59; at. no. 80; valences 1, 2. Group IIB(12). Abundance in earth's crust 0.5 ppm. Natural isotopes: 202 (29.80%); 200 (23.13%); 199 (16.84%); 201 (13.22%); 198 (10.02%); 204 (6.85%); 196 (0.146%); known isotopes range in mass number from 189 to 206. Obtained by roasting cinnabar (mercuric sulfide). General reviews: Roberts, Adv. Inorg. Chem. Radiochem. 11 (Academic Press, New York, 1968) pp 309-339; Aylett, "Group IIB" in Comprehensive Inorganic Chemistry vol. 3 (Pergamon Press, Oxford, 1973) pp 187-328; H. J. Drake in Kirk-Othmer Encyclopedia of Chemical Technology vol. 15 (Wiley-Interscience, New York, 3rd ed., 1981) pp 143-156. Review of clinical toxicology: H. B. Gerstner, J. E. Huff, J. Toxicol. Environ. Health 2, 491-526 (1977); and human exposure: Toxicological Profile for Mercury (PB99-142416, 1999) 676 pp.
Properties: Silver-white, heavy, mobile, liquid metal; slightly volatile at ordinary temp; solid mercury is a tin-white, ductile, malleable mass which may be cut with a knife. mp -38.87°; bp 356.72°; d25 13.534. Heat capacity at constant pressure (25°) 6.687 cal/mole deg. Vapor pressure (25°): 2 ´ 10-3 mm; heat of vaporization (25°): 14.652 kcal/mole: Busey, Giauque, J. Am. Chem. Soc. 75, 806 (1953). Surface tension (25°): 484 dynes/cm; electrical resistivity (20°): 95.76 mohm cm. When pure does not tarnish on exposure to air at ordinary temp, but when heated to near the boiling point slowly oxidizes to HgO. Forms alloys with most metals except iron and combines with sulfur at ordinary temperatures. E0 (aq) Hg/Hg2+ -0.854 V; E0 (aq) 2 Hg/Hg22+ -0.789 V. Soly in water (25°): 0.28 mmoles/l; data on soly in organic solvents: Spencer, Voigt, J. Phys. Chem. 72, 464 (1968). Reacts with HNO3 and hot, concd H2SO4; does not react with dil HCl, cold H2SO4, or alkalies. Reacts with ammonia solns in air to form Hg2NOH, Millon's base. Mercury salts when heated with Na2CO3 yield metallic Hg and are reduced to metal by H2O2 in the presence of alkali hydroxide. Cu, Fe, Zn and many other metals ppt metallic Hg from neutral or slightly acid solns of mercury salts. Soluble ionized mercuric salts give a yellow ppt of HgO with NaOH and a red ppt of HgI2 with alkali iodide. Mercurous salts give a black ppt with alkali hydroxides and a white ppt of calomel with HCl or sol chlorides. They are slowly dec by sunlight. Poisonous!
Melting point: mp -38.87°
Boiling point: bp 356.72°
Density: d25 13.534
CAUTION: Readily absorbed via respiratory tract (elemental mercury vapor, mercury compd dusts), intact skin, and G.I. tract, although occasional incidental swallowing of metallic mercury is without harm. Spilled and heated elemental mercury is particularly hazardous. Acute: sol salts have violent corrosive effects on skin and mucous membranes; severe nausea, vomiting, abdominal pain, bloody diarrhea; kidney damage; death usually within 10 days. Chronic: inflammation of mouth and gums, excessive salivation, loosening of teeth; kidney damage; muscle tremors, jerky gait, spasms of extremities; personality changes, depression, irritability, nervousness. Phenyl and alkyl mercurials can cause skin burns and be absorbed by the skin. Burning sensation is delayed several hours and thus gives no warning. Alkyls have affinity for brain tissue and may cause permanent damage. Phenyls are no more toxic than inorganic Hg. Antidote: Dimercaprol (BAL). See E. Browning, Toxicity of Industrial Metals (Appleton-Century Crofts, New York, 2nd ed., 1969) pp 226-242.
Use: In barometers, thermometers, hydrometers, pyrometers; in mercury arc lamps producing ultraviolet rays; in switches, fluorescent lamps; in mercury boilers; manuf all mercury salts, mirrors; as catalyst in oxidation of organic compds; extracting gold and silver from ores; making amalgams, electric rectifiers, mercury fulminate; also in dentistry; in determining N by Kjeldahl method, for Millon's reagent; as cathode in electrolysis, electroanalysis, and many other uses. Also in pharmaceuticals, agricultural chemicals, anti-fouling paints. |