Unit cell two-dimensional

Surface unit cell Two-dimensional repeating unit that fully describes the surface structure. 

Zeolite ZSM-5, as a member of the family of pentasil zeolites, has aroused tremendous interest after its first discovery by the research group of Mobile Company in the year 1972 [1]. With its adjustable framework A1 content (from 0 to about 8A1 per unit cell), two dimensional micropore channels (0.55 nm x 0.54 nm Fig. la), sinusoidal pore geometry along c axis (Fig.lb) and easy insertion of hetero-T atoms, this material plays an important role in many of crucial catalytic processes such as hydro-cracking, de-waxing, alkylation, etc., [2-5] as well as in separation of organic compounds with different sizes and shapes [6]. In the case when zeolite ZSM-5 was used as catalyst, most of reactions are diffusion-controlled [7]. This means that the product distribution largely depend on the nature and location of active sites in the crystalline framework of catalyst. Thus, the increase of the... 

FIGURE 3.18. Interstitial sites in cep unit cell, two-dimensional projection, (a) Tetrahedral sites, (b) octahedral sites. Vertical axis heights are given. 

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