Tellurium polymers

Polyatomic Chalcogen Polymers and Polymeric Tellurium Cations... 

Structural steels, tellurium in, 24 425 Structure(s), see also Chain structure Chemical structures Cocontinuous structures Controlled structure Crystal structure Molecular structure Morphology Phase structure of carbon fibers, 26 737-739 detersive systems for, 8 413t HDPE, 20 157-162 LLDPE, 20 182-184, 203-205 polyesterether elastomer, 20 72-73 polyester fiber, 20 21 polyether antibiotics, 20 137-139 polyimide, 20 276-278 polymer, 20 395-405 protein, 20 449 PTT, 20 68t... 

Some of the polymers containing phosphorous, arsenic, selenium and tellurium are shown below ... 

Dr. Clifford It is my impression that Na2Te04 (mentioned in Dr. Violet s paper) is a polymer with 6-coordination about the tellurium, not a monomer with 4-coordination. Has any recent x-ray work been done on this compound ... 

Other Substrates Deposition of cadmium was also studied on Bi, Sn and Pb [303], Ni [304], reticulated vitreous carbon [305], Ti [306], and indium tin oxide [307]. UPD of Cd on tellurium results in CdTe formation [270, 308]. Electrodes coated with conducting polymers were also used to deposit cadmium electrochemi-cally. In the case of polyaniline, the metal reduction potential corresponds to the neutral (nonconducting) state of the polymer, therefore cadmium was found to deposit on the substrate-glassy carbon electrode surface, in the open pores of the polymer film [309, 310]. 

SULFUR-, SELENIUM- AND TELLURIUM-OXYGEN RINGS AND POLYMERS... 

The key component of the optical recording system is the recording medium, which is marked in one step and read in another step with a laser beam. Many materials have been considered for the purpose, including metal-films, organic dyes, dye-loaded polymers, metal-loaded polymers, discontinuous metal films, thermal coloration systems and bilayers (1-19). Tellurium- and gold-based optical disks have been the most widely studied materials to date. 

The simplest recording medium is a bilayer structure. It is constructed by first evaporating a highly reflective aluminum layer onto a suitable disk substrate. Next, a thin film (15-50 nm thick) of a metal, such as tellurium, is vacuum deposited on top of the aluminum layer. The laser power required to form the mark is dependent on the thermal characteristics of the metal film. Tellurium, for example, has a low thermal diffusivity and a melting point of 452 °C which make it an attractive recording material. The thermal diffusivity of the substrate material should also be as low as possible, since a significant fraction of the heat generated in the metal layer can be conducted to the substrate. For this reason, low cost polymer substrates such as poly (methylmethacrylate) or poly (vinyl chloride) are ideal. 

Another hazy boundary separates polymeric and metallic substances. We have already noted the case of iodine, which can be described as a molecular solid but which might also be viewed as a two-dimensional polymer having incipient metallic properties. Elemental tellurium, whose chain structure was described earlier in this section, has pronounced metallic properties. Each Te atom is bonded to two others at a distance of 284 pm, and this connectivity leads to a helical chain. However, each Te atom is bonded to four more in other chains, at a distance of 350 pm. These longer Te-Te contacts are apparently responsible for the metallic properties. 

Liquid sulfur trioxide is used for sulfonation, especially in the manufacture of detergents. In the past, the difficulty was the instability of the sulfur trioxide. However, under the trade name Sulfans , stabilized forms of sulfur trioxide are available several patented inhibitors such as boron compounds, methane sulfonyl chloride, sulfur, tellurium, and phosphorus oxychloride inhibit crystallization or conversion to a polymer. 

Aryl tellurium halides, the postulated intermediates, are polymeric substances in which the tellurium atoms are connected by halogen bridges. The polymer network facilitates the migration of aryl groups required by this reaction10. 

The few polymeric materials containing organic groups and tellurium as repeating units are poly(alkylene tellurium), poly(arylene tellurium), and the corresponding ditellurium compounds. These polymers were prepared to allow the exploration of their electrical properties. 

Elemental tellurium can be removed by stirring the polymer in an aqueous solution of potassium cyanide for several hours3. 

The condensation of tellurium tetrachloride with a divinylbenzene-styrene copolymer produced a polymer functionalized by trichlorotelluro groups5. 

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