Pertechnetate ion

Technetium is a silvery-gray metal that tarnishes slowly in moist air. The common oxidation states of technetium are +7, +5, and +4. Under oxidizing conditions technetium (Vll) will exist as the pertechnetate ion, TcOr-. The chemistry of technetium is said to be similar to that of rhenium. Technetium dissolves in nitric acid, aqua regia, and cone, sulfuric acid, but is not soluble in hydrochloric acid of any strength. The element is a remarkable corrosion inhibitor for steel. The metal is an excellent superconductor at IIK and below. 

In complexing acid media (e.g. hydrohalogenic acids HX) the reduction of pertechnetate ions proreeds in a different way. In the works [11,13,15] it was shown that such a reduction occurred according to the scheme (1). 

The solution of (CgHj) AsTcO is passed through an ion exchange resin in the chloride form. Pertechnetate ions are strongly adsorbed while tetraphenylarsonium chloride is recovered in the runnings. Pertechnetate is then eluted from the resin by 2 N NaOH. Nitron pertechnetate is dissolved in ethyl acetate and the solution is shaken with dilute ammonia. TcO passes into the aqueous layer while the nitron remains in the ester . 

The existence of various oxidation states of technetium indicates the possibility of using polarography for its quantitative determination. Polarographic reduction of the pertechnetate ion at a dropping mercury electrode has been studied in different supporting electrolytes . 

Red blood cell labeling inhibition. Tobacco decreased the labeling of blood elements with technetium-99m and plasma proteins. This effect possibly resulted from either a direct or an indirect effect (reactive oxygen species [ROS]) of tobacco by oxidation of the stannous ion, possible damages caused in plasma membrane and/or possible chelating action on the stannous and/or pertechnetate ions . 

The tetraoxo pertechnetate ion is a much less potent oxidant than its permangano counterpart. A value of ° = —1.50 V versus NHE has been measured for the potential of the one-electron couple in Eq. (l)inCH3CN [6]. 

Technetium - In oxic seawater 99Tc appears to be present almost exclusively as the pertechnetate ion (TcOij") (Beasley and Lorz, 1986). This highly soluble and... 

Technetium(VII) oxide is a yellow solid, crystallizing in the orthorhombic space group D2)l15-Pbca and is one of the few known transition metal oxides having a molecular structure in the solid state.10 It melts at 119.5° and boils at 310.6° It dissolves in water, forming pertechnetic acid. The pertechnetate ion is known to inhibit the corrosion of steel. TechnetiumfVII) oxide is an excellent starting material for preparing pure technetium metal. 

The valuable tracer ""Tc used in nuclear medicine can be obtained as the pertechnetate ion using a Mo Tc generator (see Radioisotope Generators), which takes advantage of the equilibrium between the parent radionuchde Mo and the daughter radionuclide Tc. The separation between the two radionuclides is done on an alumina coluum by the selective elution of [ "Tc04] with a saline solution. 

The pertechnetate ion, Tc04, is often used to introduce the radioactive Tc into compounds, some of which are used as medical tracers. Unlike the isoelectronic, vividly purple permanganate ion, pertechnetate is very pale red. 

Which is the stronger oxidizing agent, permanganate ion or pertechnetate ion ... 

Chemically, radioactive molybdate Mo04 converts to radioactive pertechnetate ion (TCO4 ). The radioactive Tc04 is removed from the generator when needed. It is administered to the patient as an aqueous salt solution that has an osmotic pressure identical to that of human blood. 

In the Ph. Eur., sodium pertechnetate [ Tc] and other Tc species are analyzed by descending paper chromatography (Council of Europe 1997 a). The solvent used consists of eight parts of methanol and two parts of water. The chromatogram is developed for 2 h, dried, and the distribution of radioactivity is measured with a suitable detector. Not less than 95% of the recovered radioactivity is located in the spot corresponding to pertechnetate ion, which has an Revalue of approximately 0.6. Reduced, colloidal forms remain at the start of the chromatogram. 

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