The title compound [2(1,2,3,3a,6a-ƞ)pentalene]-[l(ƞ5)-pentamethylcyclopentadienyl]diiron, [Fe2(C8H7)-(C10H15)(C8H6)], has a metallocenic structure with the two pentalene ligands adopting an eclipsed conformation. In the central pentalene ligand, all the peripheral bonds are of similar length whereas the bridge bond is longer; there are two significantly different Fe-C distances, i.e. a mean value of 2.121(3)A for the Fe-Cbridge distances and a mean value of 2.028(3)A for the distances from the Fe atoms to all other Catoms. In the terminal pentalene ligand, the C-C and C-Fe distances in the ring bonded to the Fe atom are all similar
