# The structure of 1-(butan-2-yl)-4-tert-butylbenzene is displayed below. What is -yl on this compound and when do I use it?

I can't figure out how to use -yl on organic nomenclature and how do I use it in nomenclature. Please explain everything about the use of -yl in nomenclature.

• Think of the ending -yl as defining an adjective. The term (butan-2-yl) is an adjective modifying the noun tert-butylbenzene. No different than 3-methylhexane. [3-adjective-noun]. – user55119 May 15 '18 at 18:03

The "yl" refers to removing a hydrogen atom from a molecule making a univalent group.

Butane is

$\ce{CH3-CH2-CH2-CH3}$

To make butan-2-yl take a hydrogen atom off carbon 2:

$\ce{CH3-CH-CH2-CH3}$

Then butan-2-yl X would be

$\ce{CH3-CH(X)-CH2-CH3}$.