Cannabinoid
Length
### Length

Most classical cannabinoids are 21\-carbon compounds. However, some do not follow this rule, primarily because of variation in the length of the [side\-chain](/wiki/Side_chain "Side chain") attached to the [aromatic](/wiki/Aromatic_hydrocarbon "Aromatic hydrocarbon") ring. In THC, CBD, and CBN, this side\-chain is a pentyl (5\-carbon) chain. In the most common homologue, the pentyl chain is replaced with a propyl (3\-carbon) chain. Cannabinoids with the propyl side chain are named using the suffix *varin* and are designated THCV, CBDV, or CBNV, while those with the heptyl side chain are named using the suffix *phorol* and are designated THCP and CBDP.


What is the difference between cannabinoids with a propyl side-chain and those with a heptyl side-chain?