SILVER COMPOUND

Silver biocides have been widely used for several years in the Asia-Pacific region, and most of them are made and sold in Japan. They cost two or three times as much as ordinary antimicrobials but have now begun to penetrate the medical device market in North America and Europe. With the adoption of new surgical techniques, the medical device market is constantly changing. Infection can be a problem with endotracheal tubes, catheters and stents some of these infections are fatal. Silver compoimds are used specifically in stethoscope diaphragm covers, central venous catheters, sterilisation trays, bedpans and handles for dental instruments. 

Silver, a white, lustrous metal, slightly less malleable and ductile than gold (see Gold and gold compounds), has high thermal and electrical conductivity (see SiLVERAND SILVER alloys). Most silver compounds are made from silver nitrate [7761-88-8], AgNO, which is prepared from silver metal. 

Silver belongs to Group II (IB) of the Periodic Table. The metal has a outer electronic configuration. Silver has been shown to have three 

Only three simple silver salts, ie, the fluoride, nitrate, and perchlorate, are soluble to the extent of at least one mole per Hter. Silver acetate, chlorate, nitrite, and sulfate are considered to be moderately soluble. AH other silver salts are, at most, spatingly soluble the sulfide is one of the most iasoluble salts known. SHver(I) also forms stable complexes with excess ammonia, cyanide, thiosulfate, and the haUdes. Complex formation often results ia the solubilization of otherwise iasoluble salts. Silver bromide and iodide are colored, although the respective ions are colorless. This is considered to be evidence of the partially covalent nature of these salts. 

Silver compounds, available from commercial suppHers, are expensive. Reagent grades of sHver(I) carbonate, cyanide, diethjldithiocarbamate, iodate, nitrate, oxide, phosphate, and sulfate are available. Standardized solutions of silver nitrate are also available for analytical uses. Purified grades of sHver(I) acetate, bromide, cyanide, and iodide can be purchased silver nitrate is also made as a USP XX grade for medicinal uses (6). 

Many silver compounds are unstable to light, and are thus shipped ia brown glass or opaque plastic bottles. Silver compounds that are oxidants, eg, silver nitrate and iodate, must be so identified according to U.S. Department of Transportation (DOT) regulations. Compounds such as silver cyanide, which is toxic owiag to its cyanide content, must carry a poison label. However, most silver compounds are essentially nontoxic. 

After a certain period of time, a natural selection process will yield strains which overcome the biocidal effect. In the case of copper, the first colonizers will be organisms tolerant to copper and may be later, in turn, colonized by copper-sensitive organisms. 

The biocide will be released into the environment and can result in harmful effects. An example is tributyltin anti-fouling compounds. However, these are so toxic to marine organisms that they have been widely banned from use. 

The self-assembly of interconverting multinuclear arrays has been demonstrated recently with the supramolecular products being studied using both NOESY methods and X-ray diffraction. Treatment of a pentatopic decadentate 

The oligomerisation of dicyanoargentate(I) [and also dicyanoaurate(I)] ions in aqueous and methanolic solutions has lately been probed by UV-visible spectroscopy with results pointing to generation of metal-metal interactions between ions. Formation constants of 1.50 + 0.05 and 17.9 + 2.0 M have been obtained for [Ag(CN)2 ]2 and [Au(CN)2 ]2, respectively, at room temperature.  

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Oxidation States. The common oxidation state of silver is +1, ie,, as found in AgCl, which is used with Mg in sea- or freshwater-activated batteries (qv) AgNO, the initial material for photographic materials, medical compounds, catalysts, etc and silver oxide, Ag20, an electrode in batteries (see Silver compounds). Few compounds are known. The aqua ion [Ag(H2 O), which has one unpaired electron, is obtained... 

Tetrasilver tetroxide is a powerful oxidizer for sanitizing swimming pools, hot tubs, and industrial cooling system waters (see Water, treatment of SWIMMINGPOOLS, SPAS, AND HOT tubs). This oxide is slightly soluble and its dissociation into silver ions is enhanced by the addition of the oxidizer KgSgOg. Bivalent and trivalent silver disinfectants have been shown to be from 50 to 200 times more effective as sanitizers than monovalent silver compounds. 

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