What is the difference between a carbocation and a carbanion?

Answer 1

carbocation is when there is an excess positive charge on a carbon atom, whereas carbanion is when there is excess negative charge.

These usually happen in stabilized compounds containing either phenyl groups or double bonds that are often conjugated.

Answer 2

One has a positive charge on the carbon (for example, CH3+) while the other has a negative charge, with a lone pair of electrons (:CH3-).