Selenate ion

H2Se (hydrogen selenide, colorless), HSe (acid telluride ion, colorless), Se (selenide ion, colorless), H2Se03 (selenous acid, colorless), HSeOJ (acid selenite ion, colorless), SeO (selenite ion, colorless), H2Se04 (selenic acid, colorless), HSeOJ (acid selenate ion, colorless), SeO " (selenate ion, colorless). 

Stable, e.g. selenium compounds.6 The selenate ion exerts a toxic effect, but does not undergo any further chemical change in the plant. 

This interpretation of the Raman spectrum was verified in 1946 by Ingold Mid his co-workers [36] for mixtures of nitric acid with other concentrated acids. Thus, for example, mixtures of nitric and perchloric or selenic acids produce a high intensity 1400 cm"1 line, but not a trace of the 1050 cm"1 line. Instead of the latter, lines corresponding to the perchlorate and selenate ions appear. 

Tan, T.T.Y., C.K. Yip, D. Beydoun and R. Amal (2003). Effects of nano-Ag particles loading on TiOj photocatalytic reduction of selenate ions. Chemical Engineering Journal, 95(1-3), 179-186. 

Selenium is just below sulfur in the periodic table. We can guess that the Se04 ion is named analogously to the S04 ion. The name is selenate ion. 

A newly discovered bacterium can reduce selenate ion, SeO iaq), to elemental selenium, Se(s), in reservoirs. This is significant because the soluble selenate ion is potentially toxic, but elemental selenium is insoluble and harmless. Assume that water is oxidized to oxygen as the selenate ion... 

The only protonation reaction of the selenate ion that needs to be considered is SeO + HSeO . (V.23)... 

The selected thermodynamic data for hydrogen selenate and selenate ions, with AfG° (HSe04,298.15 K) derived in Section V.3.4.2, would then be ... 

The value of the protonation constant of the selenate ion, K, was varied systematically until a (reasonably) constant value of , independent of C, was obtained from the above equation. The result was log, = 2.0 and = — 0.1295 V. However, the equation is not quite correct as the degree of dissociation of the hydrogen selenate ion is substantially different in the two half-cells, cf. [35HAR/HAM]. The value obtained for Kx will therefore not be accepted. A recalculation of the data by the review has not been attempted. 

No primaiy data are provided, which does not permit an assessment of the result. Such data are, however, provided in [64WEL/SAL] for the sulphate ion, which apparently behaves very similar to the selenate ion with = 10 M The data are reproduced in Table A-69 and Figure A-1. The value of k was determined to be 49.5 mol -L s from the value of at [SO ] = 0 and 2 was assigned to the limiting value of ko at high sulphate concentrations, 74 mol -L s. ... 

The interaction between the selenite or selenate ion with Cu and Pb was studied by classical polarography. The measurements were carried out in unbuffered solution with 0.15 M NaN03 added as supporting electrolyte. The temperature is not mentioned. The... 

SEL/KAP] Selivanova, N. M., Kapustinskii, A. F., Zubova, G. A., Thermochemical properties of slightly soluble selenates and the entropy of the selenate ion in aqueous solution, Izv. Akad. Nauk SSSR, Ser. Khim., (1959), 187-194, in Russian. Cited on pages 225,408, 451,467, 504. 

KOL/TET2] Kolosov, 1. V., Tetsu, K., Ivanov-Emin, B. N., Korotaeva, L. G., An anion-exchange study of the interaction between scandium and selenate ions, Russ. J. Inorg. Chem., 16, (1971), 1649-1650. From a citation in this Bibliography... 

The high oxidation potential required to form the selenate ion results in the separation of sulfur and selenium in an oxidizing environment. Sulfur is oxidized to sulfate and is relatively mobile. Selenium is oxidized to selenite and is bound in a very insoluble basic ferric selenite and is immobile. 

The forms and concentration of selenium in the soil solution are governed by various physical-chemical factors expressed in terms of chemical ligands, pH, dissociation constants, solubility products, and oxidation-reduction states. In acid soils (pH 5-6.5), selenium is usually bound as a basic ferric selenite of extremely low solubility and is essentially unavailable to plants. In alkaline soils (pH 7.5-S.5), selenium may be present as selenate ions and become water soluble. 

Reactions of selenate ions To study these reactions use a 0.1m solution of potassium selenate, K2Se04, or sodium selenate, Na2Se04 - IOH2O. 

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