Solubility lanthanide ions

Solid Compounds. The tripositive actinide ions resemble tripositive lanthanide ions in their precipitation reactions (13,14,17,20,22). Tetrapositive actinide ions are similar in this respect to Ce . Thus the duorides and oxalates are insoluble in acid solution, and the nitrates, sulfates, perchlorates, and sulfides are all soluble. The tetrapositive actinide ions form insoluble iodates and various substituted arsenates even in rather strongly acid solution. The MO2 actinide ions can be precipitated as the potassium salt from strong carbonate solutions. In solutions containing a high concentration of sodium and acetate ions, the actinide ions form the insoluble crystalline salt NaM02(02CCH2)3. The hydroxides of all four ionic types are insoluble ... 

Lanthanides form soluble complexes with many inorganic and organic substances however, the nature of the bonding in these complexes has not been completely determined. There is evidence for either ionic or covalent bond formation or a combination of both. Lanthanides are complexed by inorganic ions, but not as readily as are the transition elements. The inorganic complexes are not as important... 

Figure 19-16 shows how Eu3+ can be incorporated into an immunoassay. A chelating group that binds lanthanide ions is attached to antibody 2 in Figure 19-13. While bound to the antibody, Eu3+ has weak luminescence. After all steps in Figure 19-13 have been completed, the pH of the solution is lowered in the presence of a soluble chelator that extracts Eu3+ into solution. Strong luminescence from the soluble metal ion is then easily detected by a time-resolved measurement.

The early separation of the lanthanides was beset by difficulties as a result of the similarity in size and charge of the lanthanide ions. The separations were generally based on slight differences in solubility, which were exploited through schemes of fractional crystallization. The differences in behavior resulting from a decrease in ion... 

A compound that is able to influence the relaxation times of water protons has to be paramagnetic. In the Periodic System paramagnetic ions are to be found amongst the transition metals and the rare earth metals (lanthanides). However, it was well known, that the free ions of heavy metals are toxic. Lanthanide ions form soluble complexes with ligands such as phospholipids, amino acids and proteins that are present in plasma. The liver and the skeleton are the major sites of accumulation of free metal ions. Uptake in the liver is mediated by the hepa-tocytes [2]. 

Sterically demanding alkyl or trimethylsilyl substituents provide the necessary steric saturation around the large lanthanide ions and assure a high solubility of the products in nonpolar organic solvents. 

Thorimbert and coworkers have reported the use of complexes (TBA)sH2[al-RE(H20)4 P2W17O61] (RE = La, Sm, Eu, Yb TBA=tetrabutylammonium) as Lewis acid catalysts. These complexes are soluble in organic solvents, and the water molecules on the lanthanide ions are labile, thus providing the metal centers with available coordination sites for organic substrates. These catalysts show high chemoselectivity for the competition reactions between... 

Facile ligand modification To improve the chemical and physical properties of the emitting materials, such as suitability for vapor phase deposition, solubility, stability or carrier transporting properties, modification of the ligands is necessary. Since the 4f shells of trivalent lanthanide ions are well shielded by the filled 5s and 5p orbitals, the 4f energy levels are only weakly perturbed by the environment outside of the lanthanide ions. Thus, the modification does not result in much shift in the emission wavelength. 

Supported liquid membranes, consisting of an organic solution of -octyl(phenyl)-A,iV-diisobutylcarbamoylmethylpho-sphine oxide (CMPO) and tributyl-phosphate (TBP) in decalin, were capable of selective separation and concentration of actinide and lanthanide ions from aqueous nitrate feed solutions and from synthetic nuclear wastes where the strip solution is a mixture of formic acid (FA) and hydroxylammonium formate (HAF) [106,107]. TBP is added to CMPO to improve its solubility in aliphatic diluents. Although low concentration of nitric acid was initially used as the strippant solution, a gradual... 

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