Dicobalt hexacarbonyl acetylene complexes are a family of In organocobalt compounds with the formula Co2(C2R2)(CO)6. A large variety of R groups are tolerated. They are red compounds that are soluble in organic solvents. They arise from the reaction of alkynes and dicobalt octacarbonyl:Co2(CO)8 + R2C2 → Co2(CO)6 + 2 CO