The framework topology of ZSM-22: A high silica zeolite

ZSM-22, an orthorhombic high silica zeolite (Cmcm, a = 13.86 ± 0.03Å, b = 17.41 ± 0.04Å, and c = 5.04 ± 0.02Å), has a framework consisting of 5-, 6- and 10-rings. The structure contains ferrierite sheets of the type previously found in ZSM-5, ZSM-11 and ZSM-35 and sheets of 6-rings similar to those of the rare zeolite bikitaite. The channel system is linear unidirectional and one-dimensional (noninterconnecting) with 10-membered ring openings which are 5.5 × 4.5 Å. The 10-ring channels are smaller than those found previously in ZSM-5, ZSM-11 and ZSM-35.