Nuclear transformation / Isomeric transitions/Technetium/Hot chemistry SummaryThe chemical effects of the isomeric transition of ' 5m Tc have been investigated in potassium and ammonium hexachloro-technetate(IV) in solution and solid matrix. The retention of ,5g Tc in sulphuric solution was found to be close to zero. Change of the acid concentration had no effect. Nor was 3 Μ HQ solution much different. The retentions for the solid matrices were found to be higher than 70%. The unretained 9 5g Tc appeared as cationic, hydrated Tc0 2 , [TcQ 5 (H,0)]' and TcO; species. The last species only amounted to about 1 %.

Although the distribution of 9 sg Tc amongst the different products following isomeric transition in solid samples of pertechnetates is independent of the pH of the solution in which the dissolution for analysis takes place, the same is not true if the decay takes place in solution. The ® 5g Tc appears in neutral and cationic forms as well as TCO4 and another anionic species. Introduction of scavengers into the solution suggests that this pH effect may arise from reactions of the primary ,5 ®Tc products with radiolytic products formed in the solution by Auger electrons released during the isomeric transition.

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Nuclear transfer / Isomeric transition / Technetium / Hot chemistry SummaryThe chemical effects of isomeric transition of ' ""Tc have been investigated in solid lithium, potassium and ammoniuin pertechnetate matrices. The retention of "8TC in NH^ "(»"">TcO, was about 60% and in Li"(»"")TcO^ and K"("™)TCO, higher than 70%. The unretained ' was found preponderantly as a cationic and an uncharged species. Under corresponding storage conditions the retentions for Li TcO^ were higher than for KTcO,. The influence of temperature and ambient atmosphere was studied. The samples stored in vacuum showed a higher retention than those kept in air. Thermal annealing leads to an increase in retention.

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