Ferrocenium tetrafluoroborate

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 tetrafluoroborate
Names



IUPAC name Ferrocenium tetrafluoroborate
Other names FcBF₄
Identifiers
CAS Number	1282-37-7^Y
3D model (JSmol)	Interactive image
ChemSpider	69007671
ECHA InfoCard	100.156.161
EC Number	627-836-4
PubChem CID	124204127 charge error
CompTox Dashboard (EPA)	DTXSID90746541
InChI InChI=1S/2C5H5.BF4.Fe/c21-2-4-5-3-1;2-1(3,4)5;/h21-5H;;/q3*-1;+3 Key: HOUMJOPJFCQTEL-UHFFFAOYSA-N
SMILES C1=C[CH-]C=C1.[Fe+3].C2=C[CH-]C=C2.F[B-](F)(F)F
Properties
Chemical formula	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
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314
Precautionary statements	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). Y verify (what is ^YN ?) Infobox references

Ferrocenium salts are one-electron oxidizing agents, and the reduced product, ferrocene, is inert and often readily separated from ionic products. The ferrocene–ferrocenium couple is 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. A variety of other oxidants work well also, such as nitrosyl tetrafluoroborate. Many analogous ferrocenium salts are known.

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.