Tetraaqua‐1κ4O‐bis(ɛ‐caprolactam‐1κO)‐μ‐cyano‐1:2κ2N:C‐pentacyano‐2κ5C‐iron(III)yttrium(III), a novel cyano‐bridged dinuclear complex

Using caprolactam as a ligand, the novel title cyano‐bridged yttrium(III)–ferricyanide complex, Y(caprolactam)₂(H₂O)₄Fe(CN)₆] or FeY(CN)₆(C₆H₁₁NO)₂(H₂O)₄], has been synthesized and structurally characterized. The Y atom is seven‐coordinate and has approximately pentagonal–bipyramidal stereochemistry, with water mol­ecules occupying apical positions. Of the five ligands in equatorial positions, one is the N‐bound bridging cyano group, and flanking this are two O‐­bound caprolactam moieties, which are markedly inclined towards the bridged ferricyanide moiety such that they partially envelop it. Water mol­ecules occupy the remaining two equatorial positions. The Y—N—C—Fe—C—N sequence of atoms lies on a crystallographic twofold axis and is therefore perfectly linear, which has not been observed previously in cyano‐bridged bimetallic complexes.