Kinetic analysis and mechanism of isotopic and non-isotopic exchange of 60Co doped K3Co(SCN)6-K3Fe(SCN)6 and K3Cr(SCN)6-K3Fe(SCN)6 mixed crystals

Irradiation to different γ-ray doses shows an increase in the percentage exchanged. E(%) with increasing the γ-ray dose absorbed by the mixed crystals. Isothermal annealing studies showed that the percentage exchanged increases with time up to a plateau value characteristic for each annealing temperature and type of mixed crystals investigated. Mathematical treatment of the data on the bases of various models showed that the kinetic of exchange reactions proceed by the first order kinetic equation. Electrical conductivity measurements at room temperatures showed that the solid exchange reactions do not involve redox or similar electronic processes. A mechanism based on the formation of ligand and metal vacancies and their exchange reactions has been suggested to explain the exchange reactions in the mixed crystals investigated