Heavy metal halides

The synthesis of pentacarbonyl rhenium(I) halides, Re(CO)5X, succeeded from simple and complex rhenium halides below 200 atm of CO at 200° C. The compounds are extraordinarily stable and form easily, often quantitatively, from carbon monoxide and rhenium metal in the presence of other heavy metal halides or halogen sources such as CC14. Later we prepared the corresponding carbonyl halides of manganese (67) and technetium (68) from their respective carbonyls. It was found that the corresponding binuclear tetracarbonyl halides [M(CO)4X]2 (M = Mn, Re) could be made by heating the mononuclear M(CO)5X complexes (15, 69), as well as by other methods. 

Qualitative observations made in the pioneering experiments in heavy metal halide radiochemistry evidenced some correlation between the vaporization and the adsorption energies of the compounds. This is important when judging bulk properties of new elements and compounds from their adsorption parameters. So every attempt was directed toward quantitative evaluation of the characteristics like adsorption energy or enthalpy. 

The gas phase reaction of acetylene with hydrogen chloride uses mercuric chloride (8, 9) or other heavy metal halides as catalyst. It is important that the gas streams be dry and free from arsine, phosphine, or sulfur. Because ethylene is priced substantially lower than acetylene, most recent processes substitute ethylene for acetylene, and acetylene-based vinyl chloride plants have been disappearing. 

A similar reaction consists of decomposition of the double salt of a diphenyl-halonium salt and a heavy-metal halide by a powdered metal (Reutow). It can be used for synthesis of aryl derivatives of a wide variety of metals such as mercury, tin, antimony, and bismuth.23... 

Heavy metal halide glasses also require melting in an oxygen-free atmosphere to preserve their optical properties. These glasses are often melted under a reactive atmosphere, such as CCI4 or SFg, which, due to decomposition of the atmospheric gas, contains free halide. The atmosphere acts as both a getter for oxygen, and as a source of halide to replace volatilization losses and maintain the stoichiometry of the... 

Silane is a colorless, spontaneously flammable (pyrophoric) gas. It has a choking odor and may form explosive mixtures with air. Silane will react violently with heavy metal halides and free halogens other than hydrogen chloride. 

Piping and equipment for silane service may be of steel or stainless steel construction. Piping and equipment must be designed to withstand the pressures involved. Extreme care must be taken to avoid the contact of silane with materials containing heavy-metal halides or free halogens. Silane will react violently or explosively with these compounds. 

Do not use silane in conjunction with heavy-metal halides or free halogens, with which it will react violently. Care should be taken that all components of any silane-han-... 

Nakashio et al. reported the use of lipophilic dialkyIdimethlylammonium bromides as surfactants in the formation of emulsion liquid membrane systems (22). The two long alkyl chains provided a good hydrophilicity-lipophilicity balance (HLB) to form a stable emulsion membrane. This finding led us to attempt the use of such quaternary ammonium salts in an emulsion liquid membrane system for which the ammonium salt functions not only as the emulsifying agent but also as the carrier for heavy metal halide complexes (Figure 5). 

The first to propose the fabrication of mfrared fibers from crystalline materials (AgCl) was Kapany [25] in the mid 1960s. However, it took another decade until the fabrication of polycrystalline infinred fibers was reported by Pinnow et al. [26]. These authors fabricated fibers made of thallium halide crystals, TlBr-Tll (JCRS-5). The motivation for fabricating fibers from heavy metal halides was to realize predictions of ultra low attenuation of these materials in the IR. 

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