Pentasil Pendant

This unique combination of five-membered rings is the key structural element in a family of important industrial catalysts, belonging to the silicate mineral class of the zeolites. In this model taken directly from the x-ray crystal structure, the five-membered rings are somewhat distorted - you will not find features with ideal five-fold symmetry in a regular, periodic structure as it is not possible to fill 3D space with them without creating gaps.