Ii-Zeolite molecular seeves zinefuthe elikhulu lokwahlula i-nitrogen kunye ne-oxygen. Zinesakhiwo kunye neempawu zekristale, umphezulu uluqweqwe oluqinileyo, kwaye ii-cavities zangaphakathi zinokudlala indima yokufunxa iimolekyuli. Kukho ii-pores ezidityanisiweyo phakathi kwee-cavities, kwaye iimolekyuli zidlula kwii-pores. Ngenxa yobume obucocekileyo bee-pores, ukusasazwa kobukhulu bee-pore ze-molecular seeves kuyafana kakhulu. Ii-molecular seeves zifunxa iimolekyuli ngokukhetha ngokusekelwe kubukhulu bee-pores ezingaphakathi kweekristale zazo, oko kukuthi, zifunxa iimolekyuli zobukhulu obuthile ngelixa zigxotha iimolekyuli zezinto ezinkulu.