Problem: Indicate whether or not each of the following structures is considered to be aromatic.a) A is aromatic, B is not.b) B is aromatic, A is not.c) Both A and B are aromatic.d) A and B are not aromatic.

FREE Expert Solution

Four rules for aromaticity: 

1.    Cyclic

2.    Fully conjugated

3.    Planar

4.    Huckel’s rule (4n+2 pi electrons)

  • The variable “n” stands for the number of pi electrons found in the would-be aromatic portion of a molecule. 
  • The pi electrons can be found in pi bonds (like those in alkenes and alkynes) and in lone pairs.


Structure A

1.    Cyclic: Yes

2.    Fully conjugated: Yes (pi bond and lone pair)

3.    Planar: Yes (Small ring) 

4.    Huckel’s rule (4n+2 pi electrons)

  • We have the pi bond (2 electrons) and the lone pair (2 electrons)
  • 4 electrons total
  • NOT 4n+2 electrons.

Not aromatic


Structure B



1.    Cyclic: Yes

2.    Fully conjugated: Yes (pi bonds and empty orbital/positive charge)

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Problem Details

Indicate whether or not each of the following structures is considered to be aromatic.

a) A is aromatic, B is not.

b) B is aromatic, A is not.

c) Both A and B are aromatic.

d) A and B are not aromatic.

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