👉 Pentamerism is a type of chemical reaction in which two or more molecules are joined together, typically to form new compounds. It is named after the four types of molecules that can be formed when these reactions occur: hexamers, heptamers, octamers, and dodecamers. In pentamerism, each molecule is a tetrahedral (or octahedral) shape, with three atoms in each center. The resulting compound has the same molecular structure