Cyclopentadienylchromium tricarbonyl dimer is the organochromium compound with the formula Cp<sub>2</sub>Cr<sub>2</sub>(CO)<sub>6</sub>, where Cp is C<sub>5</sub>H<sub>5</sub>. It is a dark green crystalline solid, existing in measurable equilibrium quantities with the monometallic radical CpCr(CO)<sub>3</sub>.
The six CO ligands are terminal, and the Cr-Cr bond distance is 3.281 ÃÂ , 0.06 ÃÂ longer than the related dimolybdenum compound. The compound is prepared by treatment of chromium hexacarbonyl with sodium cyclopentadienide followed by oxidation of the resulting NaCr(CO)<sub>3</sub>(C<sub>5</sub>H<sub>5</sub>).