The solid-state reactions occurring during the moderation of (n, γ) produced hot80mBr were studied in K2OsBr6-K2OsCl6, K2ReBr6-K2ReCl6, and K2OsBr6-K2SnCl6mixed crystals. The formation of the main reaction products M80mBrBr5/2-, M80mBrCl5/2-(M = Re, Os), Os80mBrBr4Cl2-, and80mBr-is attributed to the following reaction channels: (1) primary retention or bond-preservation because of insufficient recoil energy, (2) billiard-ball reaction (substitution or replacement of ligands by recoil80mBr), (3) substitution as in (2) but formation of an additional ligand vacancy which is filled by an adjacent halide ion, and (4) capture of80mBr at interstitial vacancies. From the experimental results the contributions of these reaction channels were evaluated quantitatively.