Cations Effects of Site, Charge, and Ionic Radius

Interactions with Cations Effects of Site, Charge, and Ionic Radius 

In earlier discussions, the strong or dominating contributions of cation-dipole and cation-quadrupole interactions to the total bonding were seen 

Relative Electronegativities of Zeolite Anion and Halides—Comparison of Anion Net Charges Calculated by Molecular Orbital Theory using B3LYP/LANL2DZ with NBO Method  

Cation sites are well defined in type A zeolite but are not well defined in nearly all other zeolites, including LSX (low silica X, Si/Al = 1). Most of the cation sites are hidden and are not accessible for interactions with the adsorbate molecules. 

Effects of cation sites can be best illustrated with the important system of N2/O2 on type X zeolites. Na/X (or 13X) has been used commercially for air separation since the 1970 s. Li/LSX is the best sorbent commercially available today (Chao, 1989). Mixed-cation AgLi/LSX (with 1-3% Ag cations) has been shown to be even better than Li/LSX (Yang and Hutson, 1998 Hutson, Rege, and Yang, 1999). 

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