Technetium Compounds and their Structures

The knowledge of the chemical properties of technetium has grown over the years, as indicated hy review articles and books (Dewanjee 1990 Lever 1995 Nowotnik 1994 Peacock 1966 Schwochau 1983 Steigman and Eckelman 1992). Of particular interest are the Proceedings of the International Symposium on Technetium in Chemistry and Nuclear Medicine, presenting new developments in complex chemistry of technetium and rhenium, with state-of-the-art lectures, listed at the end of this chapter under Further Reading . 

An exception is technetium sulfide (TcjSy), known as Tc-sulfur colloid (Stern et al. 1966). Scavenging molecules like phosphinimine (R3P = N-SiMe3) have been reported to incorporate TcO, producing organic molecules containing Tc(VII) (Katti et al. 1993 Singh et al. 1995). 

The redox potential of TCO4/TCO2 was found to be -1-0.738 V, and that of TCO4/TC, 

477 V (Mazzi 1989). In the presence of suitable ligands, the redox potentials of the TcO /Tc complex are dependent upon the stability of the complex itself. It depends on the ligand, in which oxidation state a complex will be stabilized. In presence of oxygen atoms Tc(VI) is not stable, it rather disproportionates to (IV) and (VII). However, if a Tc(VI) complex is very stable, no further reduction is possible. In any case, pertechne- 

The pertechnetate anion, when reduced in the presence of ligands, usually does not release all the oxygen atoms, leading to complexes in which a TcO or a TcOj core is identified. 

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