Question

Is cyclopropenyl cation, ${C_3}{H_3}^ +$ aromatic?

Answer 1

Cyclopropenyl cation is a cyclopropane with a positive charge on one carbon atom formed by the loss of one hydrogen atom. The compounds that are cyclic, planar, conjugation of pi-electrons and obeying Huckel’s rule can be defined as aromatic compounds, these are stable compounds.

Complete answer:
Cycloalkenes are alkenes arranged in a cyclic manner. Alkenes are unsaturated hydrocarbons consisting of double bonded carbon atoms. When one hydrogen atom is removed from the cyclopropene, it forms a compound known as cyclopropenyl cation which is represented by a formula of ${C_3}{H_3}^ +$ .
Aromatic compounds are the compounds that are cyclic, planar which means all the carbon atoms have $s{p^2}$ hybridization, conjugation of $\pi$ electrons, and obeying Huckel’s rule. Huckel's rule states that the compound must contain $\left( {4n + 2} \right)\pi$ electrons, where n is a positive whole number.
The structure of cyclopropenyl cation $\left( {{C_3}{H_3}^ + } \right)$ is

The above molecule is in cyclic arrangement, all the carbon atoms are $s{p^2}$ hybridized, as the double bonded are $s{p^2}$ hybridized and the carbocation is also $s{p^2}$ hybridized, the double bond and the positive charge are in conjugation, and the compound has two pi-electrons which obeys Huckel’s rule as $\left( {4\left( 0 \right) + 2} \right)\pi = 2\pi$ electrons. cyclopropenyl cation obeys all the conditions required to be an aromatic compound.
Thus, cyclopropenyl cation, ${C_3}{H_3}^ +$ is an aromatic compound.

Note:
Conjugation means the two double bonds or one double bond and charge separated by a single bond. In the above molecule, charge and double bond are separated by a single bond. Carbocation is the carbon bearing a positive charge and involves in $s{p^2}$ hybridization.