Cyclopentadienyl nickel nitrosyl is an organonickel compound with the formula . It is a diamagnetic, volatile, relatively air-stable red liquid. It has been reported to be the simplest mono-cyclopentadienyl metal complex. It is prepared by treating nickelocene with nitric oxide. The complex has C<sub>5v</sub> symmetry.
The compound reacts with lithium aluminium hydride to give the paramagnetic cluster .
The related pentamethylcyclopentadienyl complex is also known.
Cyclopentadienyl nickel nitrosyl was the subject of several patents as a fuel additive.
Its toxicity is said to be comparable to nickel tetracarbonyl.