The chemical effects of 51 Cr-neutron capture recoils and their annealing in pure K 3 Cr(CN) 6 and in mixed crystals of the type K 3 Cr(CN) 6 -K 3 Fe(CN) 6 have been investigated. The initial parent retentions vary linearly with the mole fraction in the mixed crystals. Isothermal annealing data show that the kinetics of the reactions cannot be fitted to a single rate process and the activation energy spectra obtained according to the Vand-Primak method showed no significant variations between pure and mixed crystals.