ZSM-5

thumb|Electron micrograph and structure of ZSM-5. Blue balls represent Si and red balls represent O. thumb|The structure of ZSM-5 showing the coordination tetrahedra. ZSM-5, Zeolite Socony Mobil–5 (framework type MFI from ZSM-5 (five)), is an aluminosilicate zeolite belonging to the pentasil family of zeolites. Its chemical formula is NanAlnSi96–nO192·16H2O (01/n.1.13 occurs on cooling below a transition temperature, located between 300 and 350 K.

ZSM-5 catalyst was first synthesized by Robert Argauer and George Landolt in 1969. It is a medium pore zeolite with channels defined by ten-membered rings. The synthesis involves three different solutions. The first solution is the source of alumina, sodium ions, and hydroxide ions; in the presence of excess base the alumina will form soluble Al(OH)4− ions. The second solution has the tetrapropylammonium cation that acts as a templating agent. The third solution is the source of silica, one of the basic building blocks for the framework structure of a zeolite. Mixing the three solutions produces supersaturated tetrapropylammonium ZSM-5, which can be heated to recrystallize and produce a solid.