Gadolinium selenites

Smolyakova and Serebrennikov [78SMO/SER] measured the enthalpy change of the reaction between an aqueous solution of gadolinium chloride and Na2Se03(cr). The description of the experiments and calculations is somewhat meagre. Their data have been re-evaluated as described in Appendix A and yielded the result Af// (Gd2(SeO ,)3-8H20, am, 298.15 K) = - (5168 7) kJ-moP.  

As an amorphous phase is apparently formed when gadolinium selenite is precipitated from aqueous solution, the result of this investigation is included in the review but not selected. 

No other thermodynamic data have been found for gadolinium selenites. 

Smolyakova, Efremov, and Serebrennikov [73SMO/EFR] determined the enthaipy change of the reaction between Gd2(Se04)3-8H20(cr) and a solution of barium chloride with formation of BaSe04(cr) by a calorimetric measurement. The review calculated  

The compound is precipitated from a saturated EUCI3 solution by H2Se03, washed, and dried at 105°C. As shown by DTA in H2 intense reduction occurs at 300°C, and at 400°C it reacts in H2 and H2Se mixtures to give EuSe, Kravchenko et al. [1]. 

GdH(Se03)2 2H20 is obtained by reaction of Gd203 with an excess of H2Se03 in aqueous solution. The compound is precipitated as elongated prisms. Its thermal decomposition follows the scheme  

Oxide completely free from Se02 is only obtained at Savchenko et al. [1]. 

The compound is observed as an intermediary product on heating NH4Gd(Se03)2 2.5H20 to 590 to 810°C at 910 to 1000X it is decomposed to Gd203, see p. 503 [2]. 

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Miscellaneous compounds Cesium trihydrogen selenite Lithium trihydrogen selenite Potassium selenate Methyl ammonium alum (MASD) Ammonium cadmium sulfate Ammonium bisulfate Ammonium sulfate Ammonium nitrate Colemanite Cadmium pyroniobite Gadolinium molybdate... 

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