Chlorobis(ethylene)rhodium dimer is an organorhodium compound with the formula Rh2Cl2(C2H4)4.

It is a red-orange solid that is soluble in nonpolar organic solvents.

[1][2] The complex is prepared by treating an aqueous methanolic solution of hydrated rhodium trichloride with ethylene at room temperature.

Rh(III) is reduced with oxidation of ethylene to acetaldehyde: Reflecting the lability of its ligands, the complex does not tolerate recrystallization.

Treatment with acetylacetone and aqueous KOH gives Rh(acac)(C2H4)2.