Cyclopentadienylcobalt dicarbonyl is an organocobalt compound with formula (C5H5)Co(CO)2, abbreviated CpCo(CO)2.

[1] CpCo(CO)2 was first reported in 1954 by Piper, Cotton, and Wilkinson who produced it by the reaction of cobalt carbonyl with cyclopentadiene.

[2] It is prepared commercially by the same method: Alternatively, it is generated by the high pressure carbonylation of bis(cyclopentadienyl)cobalt (cobaltocene) at elevated temperature and pressures:[1] The compound is identified by strong bands in its IR spectrum at 2030 and 1960 cm−1.

[4][5] The catalytic cycle begins with dissociation of one CO ligand forming bis(alkyne) intermediate.

Reduction of CpCo(CO)2 with sodium yields the dinuclear radical [Cp2Co2(CO)2]−, which reacts with alkyl halides to give the dialkyl complexes [Cp2Co2(CO)2R2].