Question

Question: Use the inscribed polygon method to show why the following cation is aromatic.

Short answer

Answer

Step-by-step solution

Cyclopropenyl cation

Cyclopropenyl cation consists of two $\mathbf{\pi }$electrons and is planar. So, it obeys Huckel’s rule of aromaticity for $\left(4n+2\right)\mathrm{\pi }$electrons, where $n=0$.

Inscribed polygon method

The inscribed polygon method can be used to find whether a compound is aromatic or not.

To show why cyclopropenyl cation is aromatic

In using the inscribed polygon method, always draw the vertex pointing downward.

$2\mathrm{\pi }$electrons are present, and all the bonding molecular orbitals are filled. So, it is aromatic.