FOURIER-TRANSFORM MID AND FAR IR AND NA-23 MAS NMR ANALYSIS OF FRAMEWORK VIBRATIONS AND DISTRIBUTION OF CATIONS IN ALKALI-EXCHANGED Y-TYPE ZEOLITES

The effects of alkali metal ion (Li+, K+, Rb+, Cs+) exchange on framew ork vibrations have been studied in Y-type zeolites, with NaY as the b asis of comparison. Vibrations were monitored in the 1300-250 cm(-1) r egion. It was found that the position of the bands corresponding to th e internal tetrahedral structure were insensitive, while those corresp onding to the external linkages were sensitive to the size of the ion introduced. Na-23 MAS NMR measurements revealed that Na+ ions in the s upercage can be exchanged most easily, than those in the sodalite unit s and in the the hexagonal prism.