In this video, we're going to talk about the fennel group. Now a fennel group is just basically a benzene ring as a substituent on a parent chain. Now here the parent chain can be an alkane, an alkene, an alkyne, as long as it's longer than six carbons. Remember, the formula for benzene is C6H6, but since it's acting as a substituent, we're going to deduct away a hydrogen O.
Here it becomes C6H5 connected to something else, a longer chain that's an alkane, alkene, or an alkyne. Now this is its condensed formula. If we wanted to look at its skeletal formula, remember benzene looks like this. It's a six-membered ring with alternating double and single bonds. Five of the carbons have a hydrogen, the 6th one. Remember we took away its hydrogen so it can serve as a substituent or branch group.
Connect is something larger than itself because it is a substituent. The naming convention is the location of the phenyl group and then the parent chain name. So keep this in mind. Benzene. When it becomes a substituent, we call it fennel.