CIP rule：Cahn–Ingold–Prelog priority rules

Naming convention for stereoisomers of molecules

An example of the prioritisation of structure within the CIP system. Priority is assigned according to the substitution of elements with higher atomic numbers, or other attached groups. In red is the substituent which determines the final priority (image above).[according to whom?][citation needed]

In organic chemistry, the Cahn–Ingold–Prelog (CIP) sequence rules (also the CIP priority convention; named after Robert Sidney Cahn, Christopher Kelk Ingold, and Vladimir Prelog) are a standard process to completely and unequivocally name a stereoisomer of a molecule.[1][2]: 26  The purpose of the CIP system is to assign an R or S descriptor to each stereocenter and an E or Z descriptor to each double bond so that the configuration of the entire molecule can be specified uniquely by including the descriptors in its systematic name. A molecule may contain any number of stereocenters and any number of double bonds, and each usually give...