Ferrocenium hexafluorophosphate
Ferrocenium hexafluorophosphate is an organometallic compound with the formula [Fe(C5H5)2]PF6.  This salt is composed of the cation [Fe(C5H5)2]+ and the hexafluorophosphate anion (PF−
6).  The related tetrafluoroborate is also a popular reagent with similar properties.  The cation is often abbreviated Fc+ or Cp2Fe+.  The salt is deep blue in color and paramagnetic.
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| Names | |
|---|---|
| Other names Dicyclopentadienyl iron hexafluorophosphate | |
| Identifiers | |
| 3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.157.410 | 
| PubChem CID | |
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| Properties | |
| C10H10F6FeP | |
| Molar mass | 330.999 g·mol−1 | 
| Appearance | dark blue powder | 
| Density | 1.808 g/cm3 | 
| Melting point | (decomposes) | 
| Solubility in acetonitrile | Soluble | 
| Structure | |
| monoclinic | |
| P21/c | |
| Lattice volume (V) | 1215.8(5) Å3 | 
| Hazards | |
| GHS labelling: | |
|  | |
| Warning | |
| H315, H319, H335 | |
| P261, P305+P351+P338 | |
| Safety data sheet (SDS) | External MSDS | 
| Related compounds | |
| Other anions | Ferrocenium tetrafluoroborate | 
| Related compounds | Ferrocene | 
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references | |
Ferrocenium salts are one-electron oxidizing agents, and the reduced product, ferrocene, is relatively inert and readily separated from ionic products. The ferrocene–ferrocenium couple is often used as a reference in electrochemistry. In acetonitrile solution that is 0.1 M in NBu4PF6, the Fc+/Fc couple is +0.641 V with respect to the normal hydrogen electrode.[3]
Preparation and structure
    
Commercially available, this compound may be prepared by oxidizing ferrocene with ferric salts followed by addition of hexafluorophosphoric acid.[3]
The compound is monoclinic with well-separated cation and anion; the PF−
6 may rotate freely. The average Fe-C bond length is 2.047 Å, which is virtually indistinguishable from the Fe-C distance in ferrocene.[2]
References
    
- "Ferrocenium hexafluorophosphate 388297". Sigma-Aldrich.
-  R. Martinez, A. Tiripicchio (1990). "Structure of ferrocenium hexafluorophosphate". Acta Crystallogr. C46 (2): 202–205. doi:10.1107/S0108270189005883.{{cite journal}}: CS1 maint: uses authors parameter (link)
- Connelly, N. G.; Geiger, W. E. (1996). "Chemical Redox Agents for Organometallic Chemistry". Chem. Rev. 96 (2): 877–910. doi:10.1021/cr940053x. PMID 11848774.