Isocyanide

An isocyanide (also called isonitrile or carbylamine) is an organic compound with the functional group –N⁺≡C⁻. It is the isomer of the related nitrile (–C≡N), hence the prefix is isocyano. The organic fragment is connected to the isocyanide group through the nitrogen atom, not via the carbon. They are used as building blocks for the synthesis of other compounds.

${\displaystyle \left[{\ce {R}}-{\overset {\oplus }{\ce {N}}}{\ce {#}}{\overset {\ominus }{\ce {C}}}{\ce {:\,<->R-{\ddot {N}}=C{:}}}\right]}$

General resonance structure of an isocyanide