Thorium selenites

Krylov and Chukhlantsev [57KRY/CHU] prepared thorium selenite at 323 K by adding a concentrated solution of selenious acid to a I M solution of thorium chloride. The precipitate was aged for several days in the mother liquor at this temperature, then separated and dried at 373 K. Chemical analysis confirmed the 1 2 ratio between Th and Se(lV) and the specimen was anhydrous. No X-ray diffraction measurements were performed. 

The solubility of the specimen in dilute solution of nitric or sulphuric acid was measured at 293 K. The data at pH 3 or below have been recalculated by the review, cf. Appendix A, [56CHU]. A correction for the hydrolysis of the Th ion was applied. The result for  

Nesterenko and Glybin [99NES/GLY] prepared crystalline Th(Se03)2-H20 from aqueous solution. The vapour pressure of the salt  

The auxiliary data used are not mentioned. The result is selected, as the extrapolation is comparatively short. 

The paper also reports Af//° (Th(Se03)2, cr, 298.15 K) = -(1702.5 + 5.0) kJ-mol. This datum will not be selected as it was obtained by extra-thermodynamic methods. 

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KRY/CHU] Krylov, E. 1., Chukhlantsev, V. G., Uranyl and thorium selenites, Zh. Anal. Khim., 12, (1957), 451-456, in Russian, English translation in [57KRY/CHU2]. Cited on pages 389, 391. 

NES/GLY] Nesterenko, V. P., Glybin, V. P., Crystalline thorium selenite monohydrate Synthesis and thermodynamic research of dehydration process, Czech. J. Phys., 49, (1999), Suppl. SI, 903-908. Cited on page 392. 

Thorium forms a silicide, ThSi2, two borides,2 ThB4 and ThB6, a selenate, Th(Se04)2 9 II20, and a selenite, Th(Se03)2 H20, besides numerous salts of organic acids. 

EXPLOSION and FIRE CONCERNS combustible solid NFPA rating (NA) reacts to form explosive products with metal amides contact with acids may cause formation of poisonous hydrogen selenide gas incompatible or reacts violently with barium carbide, bromine pen-tafluoride, chromic oxide, fluorine, lithium carbide, lithium silicon, metals, nickel, sodium, nitric acid, nitrogen trichloride, oxygen, potassium, potassium bromate, rubidium carbide, zinc, silver bromate, uranium, strontium carbide, and thorium carbide toxic gases and vapors may be released in a fire involving selenium, sodium selenite, sodium selenate, and selenium dioxide use water for firefighting purposes. 

No experimental information is available on aqueous selenite complexes of thorium. IX.2.3 Solid thorium selenates... 

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