Catalysis by zeolites is dependent on shape. Because zeolites are shape-selective catalysts. They are alumino silicates Which are microporous in nature. It has Honeycomb structure. That makes them shape selective. In zeolites, some si atoms are replaced by Al to form Al-O-Si network.

Reactants are very sensitive to the pore size of zeolites. Zeolites are used in petrochemical industry. Ex- ZSM-5 used to convert alcohol into gasoline.