Actinide elements precipitation reactions

In its precipitation reactions ameiicium(IIl) is very similar to the other tripositive actinide elements and to the rare earth elements. Thus the fluonde and the oxalate are insoluble and the phosphate and iodate are only moderately soluble in acid solution, whereas the nitrates, halides, sulfates, sulfides, and perchlorates are all soluble. Americium(VI) can be precipitated with sodium acetate giving crystals isostructural with sodium uranyl acetate,... 

Ko gives specific conditions for electrodeposition of the actinides from Th to Cm. He chose a buffered solution of formic, perchloric or sulfuric acid and ammonium formate and achieved high yields for up to 100 pg of Pu at current densities of 100-300 mA/cm. The deposition of all these elements occurs as a precipitation reaction at the... 

This involves the use of tertiary amine extraction of the An ions from acidic 11 M LiCl solutions. Spectroscopic studies have indicated that, in the cases of Am and Nd at least, the octahedral trianionic hexachloro complexes are extracted from 11 M LiCl. Stability constant data for the chloride complexing of Am , and Cfin media of ionic strength 1,0 have been reported. Tertiary amines also extract Pu and a study of extraction from nitrate media by trilaurylamine (TLA) in xylene has been reported. " This showed that the mass transfer rate was controlled by the reactions between Pu from the bulk phase and interfacially adsorbed TLA-HNOs. The separation of individual transplutonium elements from the Tramex actinide product may be achieved using ion exchange or precipitation techniques." ... 

It is well-known that aquo cations of heavy elements in the iii oxidation state or higher readily lose protons to form hydroxo complexes. Subsequent condensation reactions between the hydroxo complexes can then form polynuclear species in which the metal ions are linked through hydroxo (M-OH-M) or oxo (M-O-M) bridges. For the formation of polynuclear species, the pH range is critical at too low a pH the ion will exist as the simple aquocation, and at too high a pH the hydrous oxide or hydroxide precipitates. The actinide ions with oxidation number IV are particularly prone to hydrolysis and polymerization, but the v and vi oxo... 

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