Polytypism and oxo-tungstate polyhedra polymerization in novel complex uranyl tungstates

Three new uranyl tungstates, α-, β-Cs(2)[(UO(2))(2)(W(2)O(9))], and Rb(6)[(UO(2))(7)(WO(5))(2)(W(3)O(13))O(2)], have been obtained by high temperature solid state reactions. All three compounds display novel structure topologies: α- and β-Cs(2)[(UO(2))(2)(W(2)O(9))] are based upon layers with a new topology that can be related to the uranophane topology; Rb(6)[(UO(2))(7)(WO(5))(2)(W(3)O(13))O(2)] is a rare example of a non-molecular inorganic phase with layers containing oxo-tungstate trimers. The structural relationship between α- and β-Cs(2)[(UO(2))(2)(W(2)O(9))] can be assigned to polytypism.     

Synthesis and Study of Rubidium Hexauranate Rb2[(UO2)6O3(OH)8]·6H2O and Products of Its Heat Decomposition

The interaction of hydrated uranium(VI) oxide UO₃·2.25H₂O (schoepite) with an aqueous solution of rubidium hydroxide in an autoclave at 100°C has yielded rubidium uranate Rb₂(UO₂)₆O₃(OH)₈·6H₂O. Composition and structure of the obtained compound have been determined by chemical analysis, IR spectroscopy, X-ray diffraction, and differential thermal analysis. The processes of its dehydration and thermal decomposition have been studied.

     

Thermodynamic Functions of Inulin and Absolute Entropies of Polysaccharides

Russian Journal of Physical Chemistry A - In the present work temperature dependence of heat capacity of inulin has been measured for the first time in the range from 5 to 340 K by precision...