Recently, I was watching a video about separating o-chlorotoluene and p-chlorotoluene from its solution. Following was a reaction demonstrated in the video:

enter image description here

I was curious about the structure of chlorotoluene. In this, the chlorine substituent was directly inserted into the benzene ring rather that attached to carbon atom. What does the bonding signifies? Is this structural representation correct? Does IUPAC recommend it? I couldn't find such type of image on internet not in any literature and thus I am skeptical about this representation.


2 Answers 2


Yes, this graphical representation of a substituted benzene is in accordance with Graphical Representation Standards for Chemical Structure Diagrams (IUPAC Recommendations 2008).

GR-9.4 Variable attachment location

In addition to allowing the type of attachment to vary, it may also be convenient to indicate that the attachment’s location is variable as well. This type of notation should be restricted to substituents that are known to be bonded to a specific ring, but at an unspecified or unknown atom of that ring. The substituent will always replace a hydrogen atom on one of the ring atoms, and cannot be bound to any atom that lacks an attached hydrogen atom. Unless explicitly specified otherwise, such diagrams imply that the substituent may be bonded to any ring atom that has an attached hydrogen atom. (…)

substituted nitrobenzene


When you see a line coming out of an aromatic ring as shown, it is meant to suggest that the substituent (in this case chlorine) could be at any position. enter image description here

The notation is often used when a reaction on an aromatic rings afford a mixture of products (ortho, meta, para etc), but in all cases the substituent is bonded to a specific carbon, not to the ring as a whole.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.