nitrenium ions

Synonym: aminylium ions
https://doi.org/10.1351/goldbook.N04146
The cation(H2N:+) and its N-hydrocarbyl derivatives (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 (H2N:+), (R2C=N:+), still belong to the class nitrenium ions, but are more precisely designated by the term iminylium ions.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1350 (https://doi.org/10.1351/pac199567081307)