Y-type molecular sieve

Y-type molecular sieve is a microporous crystalline material with a framework structure. 

The most basic structural units constituting the framework are silicon-oxygen and aluminum-oxygen tetrahedrons. 

These tetrahedrons form quaternary rings, six Secondary structural units such as membered rings and eight-membered rings. 

These secondary structural units are then assembled with each other to form a β cage. 

The 8 β cages are arranged according to the diamond crystal style, each carbon atom in the diamond structure is replaced by a β cage, 

and the adjacent β cages are connected by Si-O-Si (Al) through a six-membered ring to form a faujasite cage, eight zeolite cages. 

The face zeolite cages are connected to each other along the three crystal axis directions through twelve-membered rings to form a unit cell. 

The twelve-membered ring is the main window of faujasite, and its pore size is about 0.74 nm.