A carbocation is a molecule in which a carbon atom bears three bonds and a positive charge. A cation containing an even number of electrons with a significant portion of the excess positive charge located on one or more carbon atoms. This is a general term embracing carbenium ions, all types of carbonium ions vinyl cations, etc. Carbocations may be named by adding the word 'cation' to the name of the corresponding radical. Such names do not imply structure (e.g. whether three-coordinated or five-coordinated carbon atoms are present). Carbocations are generally unstable because they do not have eight electrons to satisfy the octet rule.