In Fe4[Fe(CN)6]3, the counter ion and complex iron has different oxidation state.Fe4[Fe(CN)6]3⟶4Fe3++3[Fe(CN)6]4− ∴ Counter iron will have +3 oxidation state. ∴ In complex ion, x+6(CN)=−4 x+6(−1)=−4⇒x=+2 ∴ In complex, iron has +2 oxidation state. ∴ Oxidation number of iron in Fe4[Fe(CN)6]3 are+3 and +2 respectively