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 (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.[2]
 | |
 | |
 | |
| Names | |
|---|---|
| IUPAC name Ferrocenium tetrafluoroborate | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.156.161 |
| EC Number |
|
PubChem CID |
|
CompTox Dashboard (EPA) | |
| |
| Properties | |
| C10H10BFeF4 | |
| Molar mass | 272.84 g/mol |
| Appearance | dark blue powder |
| Melting point | 178 °C (352 °F; 451 K) (decomposes) |
| Solubility in acetonitrile | Soluble[citation needed] |
| Hazards[1] | |
| GHS labelling: | |
 | |
| Danger | |
| H314 | |
| P280, P305+P351+P338, P310 | |
| Safety data sheet (SDS) | External MSDS |
| Related compounds | |
Related compounds | Ferrocene |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Preparation
Commercially available, this compound may be prepared by oxidizing ferrocene typically with ferric salts followed by addition of fluoroboric acid.[2] A variety of other oxidants work well also, such as nitrosyl tetrafluoroborate.[3] Many analogous ferrocenium salts are known.[4]
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.[5]