Cyclopentadienyl nickel nitrosyl

Cyclopentadienyl nickel nitrosyl is an organonickel compound with the formula (C5H5)NiNO. 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. Its toxicity is said to be comparable to nickel tetracarbonyl. The complex has C5v symmetry.

The compound reacts with lithium aluminium hydride to give the paramagnetic cluster (C5H5)4Ni4H3.

The related pentamethylcyclopentadienyl complex (C5(CH3)5)NiNO is also known.

Cyclopentadienyl nickel nitrosyl was the subject of several patents as a fuel additive.