TEMPERATURE EFFECTS ON FORMATION AND TRANSFORMATION OF ALKALI-METAL IONIC CLUSTERS IN GAMMA-IRRADIATED ZEOLITES

Temperature effects on ionic clusters created in the alkali-metal ion-exchanged zeolites such as sodalite, A, X, and Y during gamma-irradiation were investigated using the electron spin resonance technique. The results revealed that temperature is the key factor which determines the nature of the ionic clusters being observed. The ionic clusters such as Na2+, Na3(2+), K3(2+), and Na4(3+) were observed from the corresponding zeolites. Transformation between Na2+ and Na3(2+) was found on increasing temperature, indicating delocalization of the unpaired electrons. The overall electron acceptability of the zeolites, represented by the Sanderson electronegativity, is considered to be one factor which governs the formation and transformation on the ionic clusters.