The Full Form of ZSM is‍ Zeolite Socony Mobil.

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 Na_nAl_nSi_96–nO₁₉₂·16H₂O (0<n<27). Patented^[2] by Mobil Oil Company in 1975, it is widely used in the petroleum industry as a heterogeneous catalyst for hydrocarbon isomerization reactions.

The ZSM-5 molecular sieve boasts unique and exceptional properties, which are widely employed in important processes and applications across a broad range of industries. Commonly used in converting methanol to gasoline and diesel as well as oil refining, ZSM-5 has proved superior to amorphous solid acid catalysts in reactions such as xylene isomerization, toluene disproportionation and toluene alkylation etc. Upon ion exchange or modification, H-ZSM-5 zeolites can be derived to also possess enhanced para-selectivity. All in all, the high versatility of this zeolite makes it a truly indispensable material across many industries.

The ZSM-5 molecular sieve is a highly siliceous aluminosilicate zeolite with an intersecting and three-dimensional channel system. Its chemical formula, Na_nAl_nSi_96-nO₁₉₂ · 16H₂O, shows the unit cell composition of the zeolite. In this formula the variable, n, can range from 0 to 27. This means the ratio of the amount of silicon molecules and aluminum molecules can be changed within a pretty large range with the total number of silicon and aluminum molecules at 96.^1,2