The cation ($\ce{H2N{:}^{+}}$) and its N-hydrocarbyl derivatives ($\ce{R2N{:}^{+}}$), in which the nitrogen has a positive charge, and two unshared electrons. A synonymous but less widely used term is aminylium ions. The alkylidene derivatives of ($\ce{H2N{:}^{+}}$), ($\ce{R2C=N{:}^{+}}$), still belong to the class nitrenium ions, but are more precisely designated by the term iminylium ions.