The nitrosyl dimer [{Fe(NO) 2 (Cl)} 2 ] (1) reacts with 1,1 -bis(diphenylphosphino)ferrocene (FcP 2 ) to yield [Fe(NO) 2 (Cl)] 2 (μ-FcP 2 ) (2), the structure of which has been determined. The FcP 2 moiety bridges two Fe(NO) 2 (Cl) groups symmetrically. Oxygenation of1 in the presence of FcP 2 yields [Fe(NO 3 ) 2 Cl(O 2 P 2 Fc)] (5): complex 5 catalyses the autoxidation of cyclohexene. It transfers the oxygen atoms of its nitrato groups to phosphines. When allowed to react with an excess of FcP 2 , 2 gives [Fe(NO) 2 (FcP 2 )] (4); the subsequent formation of [Fe(NO)Cl 2 (FcP 2 O)] (3) is attributed to the reaction of 4 with chlorine liberated in situ. The structure of4 was also determined.