Prefix is another part of name which appears before word root. There are two types of prefix:

  1. Primary prefix
  2. Secondary prefix

Primary Prefix:

It is used to indicate/represent alicyclic (cylic aliphatic) compounds. For this, word “cyclo” is added before word root.


cyclo + prop + ane = cyclo propane
cyclo butane

Secondary Prefix:

It is used to represent other groups like alkyl group (as a substitute/side chain) and other functional group which are not represented by secondary suffix. It is written before word root if primary prefix is absent otherwise it is written before primary prefix.

Group Secondary Prefix
-R Alkyl
-CH3 Methyl
-C2H5 Ethyl
-C3H7 propyl
-X Halo
-NO2 Nitro
-OR Alkoxy
-OH Hydroxy