Structural characterization of dehydrated gallium zeolite L

Abstract

The structure of the dehydrated gallium analog of zeolite L, K₉Ga₉Si₂₇O₇₂ has been determined by full profile analysis of powder neutron diffraction data. The gallium partitioning between the two T-sites (T = Tetrahedral species, Si, Al, or Ga) is random. The individual O-T-O angles show small but consistent deviations from the ideal tetrahedral value. The mean T4OT and T6OT angles are nearly identical in both the present and previously studied LTL-framework structures, enabling assignment of the ²⁹Si nmr spectra. The observed cation configuration is similar to that described previously for the hydrated (Na,K) aluminum zeolite L which, therefore, suggests that little change in cation distribution accompanies dehydration.