1′‐Acetyl­ferrocene‐1‐carboxyl­ic acid: an instance of hydrogen bonding in the rare dimeric acid‐to‐ketone mode

The title compound, Fe(C₆H₅O₂)(C₇H₇O)], adopts a conformation involving partial staggering of its rings and aggregates in the solid as acid‐to‐ketone hydrogen‐bonding dimers O?O = 2.720 (4) Å and O—H?O = 164°] having centro­symmetrically related components. Close intermolecular C—H?O contacts were found to both carboxyl O atoms.