Selenites reactions with

Selenosulfate is an analogue of thiosulfate wherein one of the S atoms is replaced by a Se atom. Thiosulfate and selenosulfate anions are known to have tetrahedral structure as constituting the S and Se analogues, respectively, of the sulfate anion. The isomeric thioselenate anion SSeO " is not produced by the reaction of sulfur with selenite nor is the selenoselenate ion 86203 formed from selenium and selenite. Actually, SSeOj may be produced as a metal salt by boiling an aqueous solution of selenite with sulfur, but in aqueous solution thioselenates are not stable and isomerize to selenosulfates. 

In the case of CdSe formation using the codeposition methodology, a problem was encountered early on and studied by Skyllas-Kazacos and Miller [122]. It concerned the formation of selenide ions and their reaction with the selenite starting material to form elemental Se ... 

Reaction with sodium selenate yields lead selenate, PbSe04. Similarly, with sodium selenite or selenious acid, the product is lead selenite, PbSeOs. 

Zinc forms a wide variety of other salts, many by reaction with the adds, though some can only be obtained by fusing the oxides together. The salts include arsenates (ortho, pyro, and meta), the borate, bromate, chlorate, chlorite, various chromates, cyanide, iodate. various periodates, permanganate, phosphates (ortho, pyro, meta, various double phosphates 1. die selenate, selenites, various silicates, fluosilicate. sulfate, sulfite, and duocyanate. 

Carbon monoxide serves as the sole carbon and energy source for the carboxydo bacteria under aerobic conditions. Using water as the oxygen donor, carbon monoxide oxidase catalyzes the hydroxylation of carbon monoxide, giving carbon dioxide or bicarbonate for assimilation. Most work has been carried out on the enzyme from Pseudomonas carboxydovorans.,ftJ7>W38 The activity of carbon monoxide oxidase is considerably stimulated upon anaerobic treatment with sulfide and dithionite, or by aerobic treatment with selenite. The binding of selenite to the oxidase specifically activates the CO — methylene blue reaction.1039 The molybdenum cofactor liberated from selenium-activated carbon monoxide oxidase does not contain selenium. Here, then, the... 

Bjornstedt, M., Kumar, S., and Holgren, A. 1995. Selenite and selenodiglutathione. Reactions with thioredoxin systems. Methods Enzymol. 252 209-219. 

On the (assumed) much longer time scale over which SeOj and Mn2+ begin to appear in the aqueous-solution phase from the decomposition of = Mn" - 0Se020H, Eqs. 4.52c-4.52e can be solved under an appropriate imposed condition regarding the time variation of [=MnM - 0SeO2OH] based on the surface oxidation-reduction kinetics. For example, under steady-state conditions that yield constant concentrations of the adsorbed and dissolved selenite species, Eqs. 4.52a and 4.52b lead to a constant concentration of adsorbed selenate and therefore a constant rate of selenate detachment from the mineral surface (Eq. 4.52c). If the reasonable assumption is also made that the proton reaction with =MnH - OH equilibrates rapidly, then... 

With selenite, autocatalytic behaviour was attributed to 80(8203)2. There are similar phenomena in the sulphite reaction. They will need more study. 

The data have been reconsidered by the review and the following observations were made, see also Appendix A. The solid selenium used in the experiments was obtained by reduction of a selenite solution by thiosulphate. The selenium might therefore not be in its standard state. The activity of the specimen is most likely elose enough to the standard state activity, however, since the precipitate was kept at boiling temperature for several hours. A recalculation of the side-reactions with more recent values of the auxiliary equilibrium constants made little difference to the result. The analytical data are not always consistent with the stoichiometry of Reaction (V.24) and the known initial composition of the test solution. The authors also observed this and held oxidation of iodide by initially present oxygen responsible for the discrepancies. Flowever, in some instanees the deviations from the expected concentrations are remarkably large. The deviations do not invalidate the results if equilibrium prevails, which was tested. 

Frenkel GD, Falvey D, MacVicar C. 1991. Products of the reaction of selenite with intracellular sulfhydryl compounds. Biol Trace Elem Res 30(1) 9-18. 

Dialkyl selenites, on reaction with SbCls, readily gave the monoalkoxy-derivative SbCUOR, with SeOCla as the by-product, and the acceptor properties of such mono-alkoxy species, where R = Me, Et, C2H4C1, CH2Cp3, or CH2CCl3, have been investigated. 

Vicinal H-H couplings have been applied in the structural studies of modified cyclodextrins and used as constraints for the elucidation of the conformations around the Cysc H-CyscpH bonds in the selenotrisulfide formed by the reaction of selenite with end-capped phytochelatin-2. ... 

Different distributions of selenium were observed between the crystals formed with selenite and the crystals formed with selenate. From Figure 4-1, almost uniformly distributed Se(IV) is recognized. Near the surface, Se(IV) is slightly higher than that near the center. Near the center, a small amount of Se(VI) was also detected. The partial oxidation of Se(IV) to Se(VI) was considered to be due to the following reaction with oxygen in air. 

Thionyl chloride, as well as other inorganic acid chlorides, reacts with polyols to form mixed esters (see under Sulfate esters. Chapter III). In the presence of pyridine, partial chlorohydrin formation may occur (95), Selenium oxychloride forms a selenite ester upon reaction with mannitol (96), Phosphorus pentachloride yields unsaturated chlorohydrins of mannitol and galactitol which have the composition CeHeCU (97), Extremely interesting are the so-called complexes of alditols with various inorganic polybasic acids, their salts, or anhydrides in aqueous solutions. Complexes with boric, molybdic, tungstic, and other acids, as well as the oxides of antimony and arsenic, have been reported. It is believed that these complexes are true esters with one or more moles of alditol, a chelate type of structure being involved at some point. For the hexitols a compound with boric acid such as the following is postulated (98),... 

Equilibrium Partition Coefficients. Equilibrium solvent extraction experiments are a convenient way to screen various complexing agents for suitability as selenium extractants and to assess the potential for competition from innocuous ions like sulfate. The solvent extraction experiments allow the determination of reaction equilibrium constants and distribution or partition coefficients of the selenium species between the organic (membrane) phase and the aqueous (internal or external) phase. The equilibrium constant (K ) and distribution coefficient (K ) for the reaction of selenite with the complexing agent are defined in the equations given below,... 

---