Cyclopentadienylchromium tricarbonyl dimer

Cyclopentadienylchromium tricarbonyl dimer is the organochromium compound with the formula Cp2Cr2(CO)6, where Cp is C5H5. A dark green crystalline solid. It is the subject of research it exists in measureable equilibrium quantities with the monometallic radical CpCr(CO)3.

Structure and synthesis
The six CO ligands are terminal, and the Cr-Cr bond distance is 3.281 Å, 0.06 Å 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)3(C5H5).

Related compounds

 * Cyclopentadienylmolybdenum tricarbonyl dimer
 * Cyclopentadienyltungsten tricarbonyl dimer