-1-(4--Butyl-phen-yl)-5-ethyl-4-ferrocenyl-5-hy-droxy-1-pyrrol-2(5)-one.

The title compound, [Fe(CH)(CHNO)], which is produced by the oxidation of 1-(4--butyl-phen-yl)-2-ethyl-3-ferrocenyl-pyrrole, crystallizes as a racemic mixture in the centrosymmetric space group 2/. The central heterocyclic pyrrole ring system subtends dihedral angles of 13.7 (2)° with respect to the attached cyclo-penta-dienyl ring and of 43.