Selenites and Tellurites

Te compounds have a nasty smell and should be handled in a well-ventilated fume cupboard. Use the sodium or potassium salts of each  

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Separation of Se and Te can also be achieved by neutralizing the alkaline selenite and tellurite leach with H2SO4 this precipitates the tellurium as a hydrous dioxide and leaves the more acidic selenous acid, H2Se03, in solution from which 99.5% pure Se can be precipitated by S02 ... 

Klonowska A, T Heulin, A Vermeglio (2005) Selenite and tellurite reduction by Shewanella oneidensis. Appl Environ Microbiol 71 5607-5609. 

Generally, oxo-selenates can be classified according to the oxidation state of the selenium atom as oxu-selenates(IV), and o.Yo-selenates(VI). The same applies for the respective tellurates. Besides this systematically correct naming, chemists usually use the terms selenites and tellurites instead of o. o-selenates(IV) and oxo-tellurates(IV), and selenates and tellurates instead of OAO-selenates(VI) and oxo-tellurates(VI). Therefore, both nomenclatures will be used in parallel throughout this chapter. Compared to the respective sulfur species, the oxo-selenate(IV) and oxo-tellurates(IV) ions are very stable so that numerous compounds with these anions have been prepared. 

Be is implied The proven validity of the differences method for this kind of system will enable more complex systems to be studied, like those composed of particular metal-IDA complexes with some resin and oxyanions such as selenite and tellurite. 

The coordination chemistry of aluminum with oxyanion ligands is chiefly that of the more highly oxidized ions. Nitrites and phosphites are unknown. Arsenites, sulfites, selenites and tellurites are mentioned in the early literature but have received little recent attention. 

Coordination polymers, open-framework materials, and hybrid compounds built up with various anions have been described in the literature. The most common anions employed in open-framework structures are silicates and phosphates.1-3 Metal carboxylates with a variety of structures and dimensionalities have also been described in the recent literature.4 5 In recent years, other oxyanions such as sulfate, selenate, selenite, and tellurite have also been employed to design these structures.6,7 Surprisingly, coordination polymers... 

Selenium and tellurium The elements are present as selenite and tellurite in dilute nitric acid solution. The mixture is spotted upon paper and dried thoroughly in the air. The solvent is dry n-butyl alcohol containing 4 per cent (v/v) of dry methanol. The atmosphere in the separation vessel is saturated with respect to the solvent vapour and the relative humidity is also maintained at 50 per cent by means of a saturated solution of calcium nitrate. The solvent is allowed to diffuse 8-10 cm down the strip (c. 2 hours). After evaporation of the solvent, the strip is sprayed with 0 5m tin(II) chloride in dilute hydrochloric acid. The tellurium is indicated by a black band (RF 0 1) and the selenium as an orange band (RF 0 5). It is possible to detect 1-5 pg of Se in the presence of 1 mg of Te by this method (see also Fig. VI.5g). 

Contrary to the facile oxidation of sulfite ions, that of selenite and tellurite ions by octacyano complexes do not proceed at all except if a catalyst such as OSO4 is employed. The kinetics for the Os(VIII)-cata-lyzed oxidation of SeOa (94) and TeOa " (95) ions by octacyanotungs-tate(V) and -molybdate(V) ions in alkaline medium has thus been studied. The experimental rate laws are the same and show first-order... 

AND/KAR] Andreeva, L. L., Karapet yants, M. K., Heats of formation of bismuth selenite and tellurite, Zh. Fiz. Khim., 40, (1966), 470-473, in Russian, English translation in [66AND/KAR2]. Cited on pages 202, 484. 

Schroeder HA. 1967. Effects of selenate, selenite and tellurite on the growth and early survival of mice and rats. J Nutr 92 334-338. 

Young JD, Crowley C, Tucker EM. 1981. Haemolysis of normal and glutathione-deficient sheep erythrocytes by selenite and tellurite. Biochem Pharmacol 30 2527-2530. 

Volume 26 M. R. Masson, H. D. Lutz and B. Engelen, Sulfites, Selenites and Tellurites... 

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