When a nitrile group is the highest priority functional group present in the molecule, it is named as an alkanenitrile (alkenenitrile, alkynenitrile, ...). Since the -CºN must occur at the end of a chain of carbon atoms, the carbon of the nitrile will be carbon 1 in the numbering scheme. Other functional groups are located by this numbering scheme. Since the nitrile group is always at carbon number 1, there is no need to indicate its' location.
Examples naming simple nitriles:
* note: the -yl is changed to a -yro.
** note: numbers are not needed as the nitriles must be at the ends of the chain.
Examples naming more complex nitriles: