Cupric selenates

ALP/SAY] Macalpine, G. B., Sayce, L. A., The system cupric selenate-water-selenic acid at 25°, J. Chem. Soc., (1932), 1560-1565. Cited on pages 146,295. 

MIC/CER] Micka, Z., Cermak, M., Niznansky, D., The solubility of cupric selenate and the bonding conditions in the compound Cu(Hse03)2, Collect. Czech. Chem. Commun., 55, (1990), 2441-2446. Cited on page 293. 

Cupric selenate (CuSe04) In coloring copper and copper alloys... 

Cupric selenate (CuSeOJ Tungsten diselenide (WSe2)... 

The co-reduction of copper and selenium is considered as an exception to Kroger s theory. Current-potential curves in the literature show that deposition of copper is rather compulsory to make the deposition of selenium possible. In fact, although the standard potential for Se(IV) reduction is more positive than that of copper (0.741 and 0.340 V vs. SHE, for selenous acid and cupric ion, respectively), it turns out that Se(IV) alone is reduced at more negative potentials than Cu(II). In the presence of copper, the order is reversed. 

On crystallisation, copper selenate separates, contaminated with about 1 per cent, of cupric chloride. The latter may be removed by extraction with acetone, in which it is readily soluble, whereas the selenate is only very slightly soluble after this operation the copper selenate is finally purified by recrystallisation from water. The copper may then be removed by electrolysis,1 using low current density, when selenic acid free from selenious acid and chlorine remains in the electrolyte. The solution may be concentrated until it contains about 82 per cent, of the acid by evaporating at 95° C. under reduced pressure. 

Double Copper Selenates.—Tutton11 has investigated the crystallographic properties of double selenates of the series R2Se04,CuSe04,6H20, R representing potassium, rubidium, caesium, or ammonium. They are isomorphous with the monoclinic double salts formed by cupric sulphate with the sulphates of potassium, rubidium, caesium, and ammonium.12... 

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