The exchange of Cd2+ ions, obtained by several methods, in crystalline gamma-zirconium hydrogen phosphate was investigated. The thermal behavior was studied and structural characterization of converted phases was performed. It was found that, after being heated at 320 degrees C, when the layered structure is still present, the fully exchanged cadmium material rehydrates in air and returns to the initial phase obtained at room temperature. The molecular intercalate with CdS was also prepared and characterized. Its layered structure and X-ray diffractograms matched those of the starting precursor gamma-zirconium phosphate. (C) 2000 Elsevier Science Ltd.