A carbocation is a positively charged, trivalent carbon ion that acts as a reactive intermediate in many organic reactions.
With three bonds and only six electrons, carbocations have an incomplete octet and, therefore, electron deficient. It functions as an electron acceptor and an electrophile forming new Carbon-Carbon (C-C) bonds.
The alkyl carbocation is sp2 hybridized and planar with a bond angle of 120o between the substituents. The fourth position for 2 electrons is empty and is in the form of an unoccupied p-orbital. The empty p-orbital is perpendicular to the plane of the other carbon substituents.
Based on the number of alkyl substituents on the carbon, carbocations are of three types- the primary (1o), secondary (2o), and tertiary (3o). The carbon atom with no alkyl substituents is called methyl carbocation.