Transplutonium complex

Transplutonium complexes, 3,1215-1220 Transplutonium(II) complexes, 3,1215 Transplutonium(III) complexes, 3, 1215 aliphatic hydroxy acids, 3, 1217 aqua,3,1215... 

Transplutonium(VI) complexes aqua,3,1220 carbonates, 3, 1220 carboxylates chelating, 3, 1220 halogens, 3,1220 monocarboxylates, 3,1220 nitrato, 3,1220 oxides, 3,1220 oxoanions, 3, 1220 Transport cations... 

Tricyclopentadienide complexes of many of the actinides are known (Ac = Th, U, Pu, Am, Cm, Bk, Cf). Indeed, these are the only cyclopentadienide complexes known for the transplutonium elements, where -(-3 is the most stable oxidation state. The transplutonium elements were all prepared by a microchemical procedure which utilized a melt of biscyclopentadienyl beryllium (6) according to ... 

Table 90 Complexes of Transplutonium Actinide(III) /3-Ketoenolates with P-Oxides...

Table 91 Transplutonium Actinide(III) Halides and Halogeno Complexes...

The ZEALEX Process Researchers from KRI have shown that the zirconium salt of dibutyl phosphoric acid (ZS-HDBP) was soluble in Isopar-L in the presence of 30% TBP. This super PUREX solvent, known as ZEALEX, extracts actinides (Np-Am) together with lanthanides and other fission products, such as Ba, Cs, Fe, Mo, and Sr from nitric acid solutions. The extraction yields depend on both the molar ratio between Zr and HDBP in the 30% TBP/Isopar-L mixture and the concentration of HN03 (232). Trivalent transplutonium and lanthanide elements can be stripped together from the loaded ZEALEX solvent by a complexing solution, mixing ammonium carbonate, (NH4)2C03, and ethylenediamine-N.N.N. N -tetraacetic acid (EDTA). An optimized version of the process should allow the separation of... 

The oxidation-reduction behavior of plutonium is described by the redox potentials shown in Table I. (For the purposes of this paper, the unstable and environmentally unimportant heptavalent oxidation state will be ignored.) These values are of a high degree of accuracy, but are valid only for the media in which they are measured. In more strongly complexing media, the potentials will change. In weakly complexing media such as 1 M HClOq, all of the couples have potentials very nearly the same as a result, ionic plutonium in such solutions tends to disproportionate. Plutonium is unique in its ability to exist in all four oxidation states simultaneously in the same solution. Its behavior is in contrast to that of uranium, which is commonly present in aqueous media as the uranyl(VI) ion, and the transplutonium actinide elements, which normally occur in solution as trlvalent... 

Choppin, G. R., and Unrein, P. J. Thermodynamic study ot actinide fluoride complexation, p. 97-107, in Muller, W. and Lindner, R., eds., "Transplutonium Elements," North-Holland Publ. Co., Amsterdam, 1976. 

Extraction processes (TRUEX, PUREX, Talspeak, DIAMEX, PARC, etc.) generally involve complexation of transplutonium elements by alkyl phosphines, phosphine oxides, phosphoric acids, carbamoyl phosphonates, diamides, and thiophosphinates in aqueous/organic extractions, within derivatized solid supports, or on coated particles. There are excellent reviews of the processes and significant complexes by Mathur et al. and selected chapters in The Chemistry of the Actinide and Transactinide Elements to be published in 2003. " Work on the separation for nuclear waste management in the United States, France, and Russia have been reviewed. " ... 

Phosphine oxides. Few molecular complexes of trivalent transplutonium elements have been reported. Several studies examine the extraction chemistry of Am, Cm, and Bk with a combination of /3-diketones and tri-n-alkyl phosphine oxides and tiialkylphosphates. From these, compounds reported to be of the formula AnF3(R3PO) c (An = Am, Cm R = n-octyl, Bu"0) were isolated, where L = CF3COCHCOR (R = Me, CF3, Bu ). The stoichiometry of the complexes (An P=0) was not always reported. The complex Am(CF3COCHCOCF3)3[OP(OBu )3]2 is reported to be volatile at 175 °C. ... 

The trivalent transplutonium halides have been extensively studied. Several reviews deal specifically with actinide halides. " In aqueous solution the mono- and bis-complexes have been characterized, with the formation of the latter decreasing down the halide series. For example, AmF and AmF2" have been studied, but only a very weak monochloride complex AmCP has been reported. These species are reported to have coordination numbers as high as 11, although recent EXAFS studies show that the hydration number decreases with increasing halide concentration (and ionic strength) at concentrations below which the halo complexes form. These data suggest the coordination numbers of the mixed aquo halo complexes are probably seven to ten. 

Bagnall, K. W. Edwards, J. Heatley, F. Uranium (IV) poly(pyrazol-l-yl)borate complexes—carbon-13 NMR spectra. Transplutonium 1975, Proc. 4 Int. Transplutonium Elem. Symp. Baden-Baden Sept. 1975 Muller, W. Lindner, R., Eds., North-Holland Amsterdam, 1976, 119. 

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." ... 

Dissolution of the calcium fluoride in aluminum nitrate-nitric acid oxidizes the plutonium to the tetravalent hexanitrate complex (3), while the transplutonium nuclides remain in the trivalent state. The only actinides retained by a nitrate-form anion-exchange column are thorium, neptunium, and plutonium. The uranium distribution coeflBcient under these conditions is about ten, but uranium should not be present at this point since hexavalent uranium does not carry on calcium fluoride (4). 

The chemistry of actinide ions is generally determined by their oxidation states. The trivalent, tetravalent and hexavalent oxidation states are strongly complexed by numerous naturally occurring ligands (carbonates, humates, hydroxide) and man-made complexants (like EDTA), moderately complexed by sulfate and fluoride, and weakly complexed by chloride (7). Under environmental conditions, most uncomplexed metal ions are sorbed on surfaces (2), but the formation of soluble complexes can impede this process. With the exception of thorium, which exists exclusively in the tetravalent oxidation state under relevant conditions, the dominant solution phase species for the early actinides are the pentavalent and hexavalent oxidation states. The transplutonium actinides exist only in the trivalent state under environmentally relevant conditions. 

Choppin, G.R. and Unrein, P.J., "Thermodynamic Study of Actinide Fluoride Complexation", Transplutonium Elements, W. 

Transplutonium(IV) complexes, 1219 halogeno, 1219 3-ketoenolates, 1219 oxides, 1219 tetrahalides, 1219... 

Transplutonium(V) complexes, 1219 aqua,1219 carbonates, 1220 halogens, 1220 monocarboxyiates, 1220 oxalates, 1220 oxides, 1219... 

Transplutonium(VI) complexes aqua,1220 carbonates, 1220 carboxylates chelating, 1220 halogens, 1220 monocarboxyiates, 1220 nitrato, 1220 oxides, 1220 oxoanions, 1220 Triethanolamine alkali metal complexes, 23 Triethylamine, 2,2, 2"-trimethoxy-alkali metal complexes, 24 Trimolybdates, 1032 Trithioarsenates, 249 1,3,6,2-Trithioarsocane, 2-chloro-, 249 Trithioraolybdates, 1378 Trivanadates, 1027... 

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