4-CL-PVP Crystals for sale 4-CL-PVP Crystals, also known as 4-Chloro-α-PVP, is a research chemical belonging to the cathinone class. The IUPAC name for 4-CL-PVP is 1-(4-chlorophenyl)-2-(pyrrolidin-1-yl)pentan-1-one, and its CAS number is N/A. In its crystal form, 4-CL-PVP appears as a fine, white crystal with a high level of purity, typically 98.0% or higher. This compound is highly sought after by researchers studying the effects of cathinones on the brain and behavior due to its potent and unique properties.