Rhenium perrhenate ions

A greater tendency of rhenium complexes (compared to technetium analogues) to expand their coordination numbers has been invoked to rationalize the stronger interaction of the perrhenate ion with carboxylate ligands. This association has been suggested as a possible cause of the different quantitative biodistribution and excretion characteristics of pertechnetate and perrhenate perrhenate is accumulated in thyroid to a lesser extent and renally excreted more rapidly than pertechnetate [6]. 

Bimetallic platinum-rhenium catalysts can be prepared in aqueous acid medium, under hydrogen flow, by a redox reaction between hydrogen activated on a parent platinum-alumina catalyst and the perrhenate ion ReO4. ... 

These include the simplest ion-association systems in which bulky cations and anions are extracted as pairs or aggregates without further coordination by solvent molecules. An example of this type of system is the extraction of manganese or rhenium as permanganate or perrhenate into chloroform by association with the tetraphenylarsonium cation derived from a halide salt... 

The ratio of the distribution coefficients of pertechnetate and perrhenate is about 1.6 to 2, comparable to adjacent rare earth metals. Technetium and rhenium may be separated by ion-exchange chromatography. However, efficient separations require some care and tend to be slow. On the other hand, cation exchange resins adsorb technetiiun only to a negligible extent so that pertechnetate can be rapidly separated from cationic elements . 

Rhenium (Re, at. mass 186.21) occurs mainly in oxidation states VII, V, and IV. Rhenium(VIl) compounds are the most stable. The colourless perrhenate, ReOT ion exhibits weak oxidizing properties. The chemical properties of rhenium resemble those of Mo and Mn. Rhenium(V) and (IV) form halide, oxalate, and tartrate complexes. 

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