High Quality Content by WIKIPEDIA articles! A persistent carbene (also known as stable carbene or Arduengo carbene) is a type of carbene demonstrating particular stability. The best-known examples are diaminocarbenes with the general formula (R2N)2C:, where the `R`s are various functional groups. The groups can be bridged so that the carbon with unfilled orbitals is part of an heterocycle, such as imidazole or triazole.