Chemical effects of nuclear transformations in mixed crystals. Part 10. Chemical effects of the 37Cl(n,.gamma.)38Cl nuclear reaction in dipotassium hexachloroosmate(IV)-dipotassium hexabromoosmate(IV) mixed crystals

Abstract

The solid-state reactions occurring during the moderation of recoiling /sup 38/Cl, produced by the (n,..gamma..) reaction, have been studied in K/sub 2/OsCl/sub 6/-K/sub 2/OsBr/sub 6/ mixed crystals. The main products are Os/sup 38/ClCl/sub 5//sup 2 -/, Os/sup 38/ClBr/sub 5//sup 2 -/, and /sup 38/Cl/sup -/, but even the more intimately mixed species Os/sup 38/ClCl/sub n/Br/sub 5-n//sup 2 -/ (n = 1, ..., 4) are obtained in significant amounts. The most important reaction found is the replacement process (billiard-ball process). In some cases the recoil atom interacts with more than one ligand and intermediate ligand vacancy (denoted by square) species Os/sup 38/ClCl/sub n/square/sub 5-n//sup 2 -/ and Os/sup 38/ClBr/sub n/square/sub 5-n//sup 2 -/ (n = O, ..., 4) are formed. The vacancies are assumed to be filled by mobile halides from the lattice. From the products Os/sup 38/ClCl/sub n/Br/sub 5-n//sup 2 -/ (n = O, ..., 5) and /sup 38/Cl/sup -/ and their yield dependence on the mixed crystal composition the following results were obtained with the help of the program PRIMULA: interstitials 11%, primary retention 5%, replacement 62%, replacement plus one additional vacancy 14%, replacement plus two or more additional vacancies 7%. These results together with some experiments with K/submore » 2/ReCl/sub 6/-K/sub 2/ReBr/sub 6/ targets are in accordance with all other so far known /sup 36/Cl and /sup 82/Br recoil reactions in K/sub 2/M'Cl/sub 6/-K/sub 2/M''Br/sub 6/ mixed crystals. They do not confirm the reported ligand vacancy transfer mechanism (kinetic theory) elaborated for /sup 38/Cl recoil atoms.« less