An evaluation of E° (3/2) redox potentials of lanthanides and actinides with fqd electronic configuration is achieved. It takes into account the known equations already given for elements with fq electronic configuration and a proposed correction due to the fqd electronic stabilization.
Authors:A. Elyayaoui, S. Boulhassa, and R. Guillaumont
We have investigated the behaviour of109Cd, in two-phase systems: (HDEHP–C6 H6/ H3 PO4–HClO4–LiOH, =0.2), as a function of the independent equilibrium parameters which define the system: pH, equilibrium concentration of H3 PO4 and total concentration of HDEHP in the organic phase. The data have been interpreted in terms of the existence of phosphoric complexes characterized by their order 1 with regard to H3 PO4 and their charge z. The l and z. values are: 0<1<2, z=–2, 0, 1, 2 for the following ranges: 0.7<pH<2.7 and CH3 PO4<4M. Stability constants of the predominant complexes have been obtained. Finally, a formulation of these complexes has been proposed on the basis of partial charge of the atoms. Some complexes, could be formulated as hydroxy-phosphoric species, resulting from competition between hydroxy and dihydrogenophosphate anions. In concentrated phosphoric acid (CH3 PO4=4M), complexation of cadmium is not more than 25%.
Authors:B. Fourest, N. Hakem, J. Perrone, and R. Guillaumont
The advantages of the capillary electrophoresis method, known to be highly selective, have been tested on some standard latex colloids and nanoparticles of thorium phosphate, investigated separately or in mixtures. The results have been compared to those obtained by laser Doppler velocimetry. Both methods appear as complementary: capillary electrophoresis is more efficient to point out very fine particles among others, but is more restricting about the supporting medium.