RadiochimicaAct» As E-p can be replaced by its numerical value obtained in (8) and each quantity in the last term of (23) is known from experiments, we obtain : Ε έ ' = 8.5 -3.0 = 5.5 kcal/mol.This value corresponds to the experimentally observed value (5.6 kcal/mol) which is already shown in (9). Thus, such chemical reactions as are shown in (13) and (14) might give a possible explanation for the annealing process of [CO*(NH 3 ) 6 C1] 2 + or Co* 2 +. The above mentioned experimental results and discussion would lead us to the following model for the mechanism of the recoil phenomena of 38 C1 or M Co in the [Co(NH 3 ) e ]Cl 3 crystal. The recoil atoms of 38 C1 or eo Co which are produced by the (η, γ) -reaction in the [Co(NH 3 ) e ]Cl 3 crystal have a recoil energy of the order of 10,000 kcal/mol and can readily break the bond of the complex salt. Thus, local fragmentation occurs and systems consisting of unstable fragments are produced in the neighborhood of the recoil atoms. These fragments are immediately rearranged in the hot-zone yielding a group of such chemical species as [CO(NH 3 ) 6 ] 3 +, [CO(NH 3 ) 5 C1] 2 +, CO 2 + and/or Co 3 +, NH 3 ,Cl~, etc. These chemical species are considered to be rather stable, but there are still some physical defects and instabilities in the crystal lattice as well as some local disturbances in its composition. In these unstable systems, chemical reactions occur between the above mentioned species which lead to more stable systems. These processes are to be observed as the thermal annealing shown in Fig. 2, 3, or 4. We consider them to be of an essentially chemical nature, and the backreaction of (11), or the reactions of (13), (14) may well occur among them. By this model, the formation of 38 C1 or ®°Co in the form of [CO(NH 3 ) 5 C1] 2 + can also be explained. SummaryThermal treatment on chromic ( sl Cr)-doped potassium Chromate results in the incorporation of 51 Cr activity into the Chromate form. Measurements of the isothermal kinetics of this incorporation give "annealing" curves similar to those obtained in Szilard-Chalmers studies on potassium Chromate. It is concluded that transfer annealing may play an important role in Szilard-Chalmers annealing processes in potassium Chromate.

SummaryClose quantitative similarity is observed between the kinetics of thermal annealing of chromium-51 in neutron irradiated, inactive-Cr(III)-doped potassium Chromate and in

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Man kann daraus schließen, daß die Wassermoleküle auch im Alaun sehr beweglich sind -ähnlich wie im flüssigen Wasser -, während durch die Gerüststruktur des Alauns der niedrige Frequenzfaktor bedingt ist.Herrn Dr. K. HEUMANN danken wir für die Hilfe bei den massenspektrometrischen Untersuchungen. Dem Deutschen Kunststoff-Institut sind wir für die Über-lassung des Mikrotoms zu Dank verpflichtet. SummaryIt is suggested that the increase of retention on annealing above 100 °C in neutron irradiated chromâtes may be explained by a solid state transfer mechanism. A re-orientation of the oxygen bonds around the intruder chromium can alter the oxidation state of the latter. Also in a potassium sulfate matrix doped with Cr(III), Chromate ions are formed on heating.

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