The concept that a positive or negative charge on a carbon-carbon double bond is not stable is related to the reactivity and electronic structure of organic molecules. In organic chemistry, a double bond consists of a sigma bond (σ) and a pi bond (π). The pi bond involves the overlap of p orbitals, and the electrons in the pi bond are relatively loosely held compared to the sigma bond.
When a molecule carries a positive or negative charge on a carbon atom within a double bond, it disrupts the distribution of electrons and can lead to instability.
