Tellurium high-temperature reactions

PbTe is the sole telluride of lead and occurs in nature as the mineral altaite. It may be synthesized by high-temperature reaction of stoichiometric quantities of the elements, or by the action of tellurium powder on a boiling solution of lead salt. 

The tetrafluorides of selenium and tellurium are similar to SF4 both structurally (in the gaseous molecules) and in terms of reactivity, ffowever, the bonding in condensed phases is different and leads to several types of structures. Selenium tetrafluoride can be prepared by combining the elements, but it can also be obtained by the reaction of Se02 with SF4 at high temperature. The tellurium compound can be prepared by the reaction of SeF4 and Te02 at 80 °C. 

The chloride has no action on selenium dioxide even at high temperatures or under great pressure.2 Sulphuryl chloride reacts with tellurium with the sulphuryl chloride in excess the reaction is ... 

Similar p-T relationships exist also in the liquid state in sulfur, selenium, and tellurium. Gee (37) has studied the polymerization of liquid sulfur extensively. At high temperatures at atmospheric pressure all three elements show a thermally induced dissociation of the liquid chain structure with a gradual change toward a lower resistance liquid (38,39, 40,41,42), In the liquid state p-T reaction boundaries have been observed in sulfur (18, 43) and tellurium (31, 44). For sulfur these are consistent with the high temperature atmospheric-pressure data (39,40). For tellurium, however, the low pressure extrapolation of the liquid boundaries must be nonlinear to achieve consistency. The p—T reaction boundaries in the liquid for sulfur are plotted in Figure 1. 

Backed by the same advantages of ILs as a reaction medium, i.e. strong surface binding and the high-temperature operating window, microwave-assisted synthesis of single-crystalline tellurium nanorods and nanowires has been reported recently [38]. Monodisperse chromium nanoparticles could be made by thermolysis of a Fischer carbene complex [39]. 

Without either spray droplets or flooded pathways, substantial fractions of radionuclides released from the degrading reactor fuel can be retained within the reactor coolant system. Results of some example calculation for radionuclide retention in the reactor coolant systems for various types of accidents are shown in Table III-l. The natural retention of radionuclide vapors oeeurs because the vapors either condense on surfaces or react with these surfaces. Depending on the surface temperature and the duration of its exposure to high temperature steam, the surface material is either ehromium oxide (Cr203) or iron oxide (Fe304 y). Both of these materials are expected to be reactive toward cesium-bearing vapours and strontium or barium vapors. Stainless steel lead screws above the core at Three Mile Island were found to have captured cesium by reaction with silica impurities in the steel. Metallic nickel inclusions in the oxide films on surfaces within the reactor coolant system are reactive toward tellurium whether it is in the metallic state or present as TeO or SnTe. 

In one instance, a related tellurium complex has been reported. Reaction of KS2CN(CH2CH20H)2 with a mixture of the elements, molybdenum, tellurium, and iodine at high temperature leads to the isolation of [Mo3(p -Te)(p-Te2)3 S2CN(CH2CH20H)2 3]I (1005). 

Typical procedure. A mixture of the carbonyl compound (0.01 mol), the active methylene compound (0.01 mol) and tellurium(lV) tetrachloride (0.001 mol) was thoroughly mixed at room temperature. After being stirred for 5 min, the mixture was heated and continuously stirred at 80°C in an oil bath (20-75 min). The reaction was cooled at room temperature and treated with a solution of 1% aqueous alcohol. The product was extracted with methylene chloride, washed with water. After drying over Na2S04 the solvent was removed in vaccuo over rotatory evaporator to obtain the product in high purity. 

The photolytic procedure is performed by irradiation in benzene with a high-pressure mercury lamp, at room temperature, in the presence of atmospheric oxygen. The reaction is accompanied by deposition of elementary tellurium. 

The exothermal nature of certain components may be surprisingly high the mixture Ti Sb Pb = 48 23 29 is primed at 570 °C (1060°F), and the reaction temperature attains 1000 °C (1830°F). Other combinations include magnesium-silicon, magnesium-tellurium, magnesium-tin and magnesium-phosphorus. 

Bis[trifluoromethyl] Ditellurium An apparatus for irradiation consisting of a reaction vessel, a low-temperature (— 25°) cooler with argon adapter, and an external mercury high-pressure lamp (Heraeus, TQ 150) is assembled. Under an atmosphere of argon 2.65 g (10 mmol) bis[trifluoromethyl] tellurium, 13.6 g (200 mmol) furan, and several glass rings are plaeed into the reaction vessel. The mixture is irradiated for 54 h and stirred to remove the tellurium mirror from the walls of the reaction vessel. The solvent is distilled at atmospheric pressure until the bath temperature reaches 80°. The residue is distilled at 0.001 torr by increasing the temperature slowly from — 78° to + 25° yield 43% b.p. 120°/760 torr. 

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