Protonation of Ferrocene: A Low‐Temperature X‐ray Diffraction Study of [Cp2FeH](PF6) Reveals an Iron‐Bound Hydrido Ligand

Ferrocene, Cp₂Fe, is quantitatively protonated in a mixture of liquid HF/PF₅ to yield [Cp₂FeH](PF₆), which was characterized by ¹H/¹³C NMR and ⁵⁷Fe Mössbauer spectroscopy as well as single‐crystal X‐ray diffraction analysis. X‐ray diffraction analysis at 100 K revealed a disordered, iron‐coordinated hydrido ligand, which was unambiguously located by aspherical atom refinement at 100 K, and by analyzing the non‐disordered crystal structure at 30 K, revealing a non‐agostic structure.