Chemical effects of nuclear transformations in mixed crystals. Pt. 11

The solid-state reactions occurring during the moderation of (n, γ) produced hot 82Br have been studied in K2OsBr6-K2OsCl6 mixed crystals. The main products are Os82BrBr2/5-, Os82BrCl2/5-, and 82Br-, but even the more extensively mixed species Os82BrBr4Cl2- and Os82BrBrCl2/4- are obtained in significant amounts. The most important reaction found is the replacement process (billiard-ball process). In some cases the recoil atoms interact with more than one ligand and intermediate ligand vacancy complex anions Os82BrBrn□2/5--n and Os82BrCln□2/5--n (n=0-5) are formed. The vacancies are assumed to be filled by mobile halides from the lattice. From the fractions of Os82BrBrnCl2/5--n (n=0-5) and 82Br- and their dependence on the mixed crystal composition the following results were obtained with the help of the program PRIMULA; 5-15% interstitirals, 5-6% primary retention, 51-65% replacement, 11-19% replacement plus one additional vacancy, 6-10% replacement plus two or more additional vacancies. A small reactor effect is accounted for by different neutron energy spectra. (orig.)