Biferrocene

Biferrocene
Names
	IUPAC name 1,1"-Biferrocene
Identifiers
CAS Number	1287-38-3;
3D model (JSmol)	Interactive image;
ChemSpider	10157133;
PubChem CID	11984633;
	InChI InChI=1S/C10H8.2C5H5.2Fe/c1-2-6-9(5-1)10-7-3-4-8-10;21-2-4-5-3-1;;/h1-8H;21-5H;;/q-6;2*-1;; Key: CEMHVYUXQJEPPO-UHFFFAOYSA-N;
	SMILES C1=C[CH-]C=C1.[Fe+2].C2=C[C-](C=C2)[C-](C=C3)C=C3.[Fe+2].C1=C[CH-]C=C1;
Properties
Chemical formula	C20H18Fe2
Molar mass	370.054 g·mol−1
Appearance	dark orange solid
Melting point	239–240 °C (462–464 °F; 512–513 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Biferrocene is the organometallic compound with the formula [(C₅H₅)Fe(C₅H₄)]₂. It is the product of the formal dehydrocoupling of ferrocene, analogous the relationship between biphenyl and benzene. It is an orange, air-stable solid that is soluble in nonpolar organic solvents.

Biferrocene can be prepared by the Ullmann coupling of iodoferrocene. Its one-electron oxidized derivative [(C₅H₅)Fe(C₅H₄)]₂⁺ attracted attention as a prototypical mixed-valence compound.

A related compound is biferrocenylene, [Fe(C₅H₄)₂]₂ wherein all cyclopentadienyl rings are coupled into two fulvalene ligands.