Primary suffix is written immediately after the word root, according to the IUPAC nomenclature of an organic compound. It represents the presence of a specific type of unsaturation in the compound.
Given below are the primary suffix used for the different types of bonds that are present between the carbon atoms in a chain.
Nature of Carbon ChainPrimary SuffixGeneric nameSaturated, C - C-aneAlkaneUnsaturated, C = C-eneAlkeneUnsaturated, C ≡ C-yneAlkyne