The migration of metal ions during solid-state exchange was studied by investigating the effect of grinding force and calcination conditions on the incorporation of Pd in zeolite NaX using various Pd salts as precursors. At temperatures lower than 600 degrees C, it was found that PdCl2 and Pd(NH3)(4)Cl-2 lead to a significant Pd exchange whereas no Pd incorporation takes place with Pd(NO3)(2) as precursor. The grinding force influences the Pd2+ exchange occurring in the subsequent calcination procedure. In the case of Pd(NH3)(4)Cl-2/NaX, the grinding also causes a decomposition of:he precursor metal salt to Pd(NH3)(2)Cl-2 and a change in the crystal structure as shown by X-ray diffraction. During the calcination of PdCl2/NaX samples the precursor salt is transformed according to the following scheme:beta-PdCl2(400 degrees C) under right arrow alpha-PdCl2 (500 degrees C,O-2) under right arrow PdO7 (750 degrees C) under right arrow Pd-0The Pd species are incorporated in the zeolite in two stages, one occurring at about 400 degrees C via gas phase transport of Pd6Cl12 molecules into the supercages followed by a transfer of fragments to the smaller zeolite cages and a second one occurring between 600 and 700 degrees C via surface migration starting from PdO species.