Ferrocenium tetrafluoroborate
{{chembox
| Watchedfields = changed
| verifiedrevid = 429060751
| ImageFile1 = Ferrocenium_tetrafluoroborate.svg
| ImageFile2 = Ferrocenium-tetrafluoroborate-3D-vdW.png
| ImageFile3 = FcBF4.jpg
| IUPACName = Ferrocenium tetrafluoroborate
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 1282-37-7
| EINECS = 627-836-4
| PubChem = 124204127
| PubChem_Comment = charge error
| ChemSpiderID = 69007671
| SMILES = C1=C[CH-]C=C1.[Fe+3].C2=C[CH-]C=C2.F[B-](F)(F)F
| InChI =
}}
|Section2={{Chembox Properties
| Formula = C10H10BFeF4
| MolarMass = 272.84 g/mol
| Appearance = dark blue powder
| Density =
| MeltingPtC = 178
| MeltingPt_notes = (decomposes)
| BoilingPt =
| Solubility =
| SolubleOther = Soluble{{cn|date=January 2013}}
| Solvent = acetonitrile
}}
|Section3={{Chembox Hazards
| Hazards_ref = {{cite web |title=Ferrocenium tetrafluoroborate 482358 |url=https://www.sigmaaldrich.com/catalog/product/aldrich/482358 |website=Sigma-Aldrich}}
| GHSPictograms = {{GHS05}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|314}}
| PPhrases = {{P-phrases|280|305+351+338|310 }}
| ExternalSDS = [http://msds.chem.ox.ac.uk/FE/ferrocenium_tetrafluoroborate.html External MSDS]
| FlashPt =
| AutoignitionPt =
}}
|Section8={{Chembox Related
| OtherCompounds = Ferrocene}}
}}
Ferrocenium tetrafluoroborate is an organometallic compound with the formula [Fe(C5H5)2]BF4. This salt is composed of the cation [Fe(C5H5)2]+ and the tetrafluoroborate anion ({{chem|BF|4|−}}). The related hexafluorophosphate is also a popular reagent with similar properties. The ferrocenium cation is often abbreviated Fc+ or Cp2Fe+. The salt is deep blue in color and paramagnetic.
Ferrocenium salts are sometimes used as one-electron oxidizing agents, and the reduced product, ferrocene, is inert and readily separated from ionic products. The ferrocene–ferrocenium couple is often used as a reference in electrochemistry. The standard potential of ferrocene-ferrocenium is dependent on specific electrochemical conditions.
Preparation
Commercially available, this compound may be prepared by oxidizing ferrocene typically with ferric salts followed by addition of fluoroboric acid.{{cite journal|first1=N. G.|last1= Connelly|first2= W. E.|last2= Geiger| title=Chemical Redox Agents for Organometallic Chemistry|journal=Chemical Reviews|year= 1996| volume= 96|issue=2| pages= 877–910| doi=10.1021/cr940053x| pmid=11848774}} A variety of other oxidants work well also, such as nitrosyl tetrafluoroborate.{{cite journal | title = Solvent and electrolyte effects on the kinetics of ferrocenium-ferrocene self-exchange. A reevaluation | first1= Roger M.|last1= Nielson|first2= George E.|last2= McManis|first3= Lance K.|last3= Safford|first4= Michael J. |last4=Weaver | journal = J. Phys. Chem. | doi = 10.1021/j100342a086 | year = 1989 | volume = 93 | issue = 5 | pages = 2152}} Many analogous ferrocenium salts are known.{{cite journal|first1=J.|last1= Le Bras|first2= H. |last2=Jiao |first3=W. E. |last3=Meyer |first4=F.|last4= Hampel |first5= J. A.|last5= Gladysz |title=Synthesis, Crystal Structure, and Reactions of the 17-Valence-Electron Rhenium Methyl Complex [(η5-C5Me5)Re(NO)(P(4-C6H4CH3)3)(CH3)]+ {{chem|B(3,5-C|6|H|3|(CF|3|)|2|)|4|−}}: Experimental and Computational Bonding Comparisons with 18-Electron Methyl and Methylidene Complexes |journal=J. Organomet. Chem.|date= 2000 |volume= 616 |pages= 54–66 |doi=10.1016/S0022-328X(00)00531-3}}
Structure
According to X-ray crystallography, the structures of the metallocene component of FcBF4 and the parent ferrocene are very similar. The Fe-C distances in the cation are 209.5 pm, about 2% longer than the Fe-C distances in ferrocene.
References
{{reflist}}
{{iron compounds}}
{{Tetrafluoroborates}}