# What do aromatic compounds contain?

A benzene, or so-called aryl ring, ${C}_{6} {H}_{6}$, that may be substituted with heteratoms or hydrocarbyl groups.
What characterizes benzene as aromatic as is the presence of $6$ $\pi$ electrons constrained in a ring, to give a carbocycle. Some chemists may draw this as $\text{1,3,5-cyclohexatriene}$; younger chemists may write this as a hexagon with a circle circumscribed within; the $6$ $\pi$ electrons are delocalized around the ring, and are not associated with any particular carbon.