An isopropyl carbocation is a type of intermediate species that has a positive charge on a carbon atom in a propyl group. The structure of an isopropyl carbocation would have the following features:
A positively charged carbon atom at the center, which has three single bonds to three other atoms.
The carbon atom with the positive charge would have a sp2 hybridization, meaning that it would have three orbitals in a plane and one unoccupied p orbital perpendicular to the plane.
Two of the single bonds would be to hydrogen atoms, and the third single bond would be to a carbon atom, forming a propyl group.
It should be noted that carbocations are highly reactive species and tend to rapidly rearrange or react with other species to form more stable species.