Lithium cyclopentadienide

Lithium cyclopentadienide is an organolithium compound with the formula C₅H₅Li. The compound is often abbreviated as LiCp, where Cp⁻ is the cyclopentadienide anion. Lithium cyclopentadienide is a colorless solid, although samples often are pink owing to traces of oxidized impurities.

Lithium cyclopentadienide

Names
Other names lithium cyclopentadienylide, cyclopentadienyllithium, LiCp
Identifiers
CAS Number	16733-97-4 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.156.001
EC Number	627-659-2
PubChem CID	14063469
CompTox Dashboard (EPA)	DTXSID40555241
InChI InChI=1S/C5H5.Li/c1-2-4-5-3-1;/h1-3H,4H2;/q-1;+1 Key: CSOHRTAOCDVTQU-UHFFFAOYSA-N
SMILES [Li+].C1C=CC=[C-]1
Properties
Chemical formula	C5H5Li
Molar mass	72.04 g·mol−1
Appearance	colorless solid
Density	1.064 g/cm3
Solubility in water	decomposition
Solubility	THF, dimethoxyethane
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

Preparation, structure and reactions

Lithium cyclopentadienide is commercially available as a solution in tetrahydrofuran. It is prepared by treating cyclopentadiene with butyllithium:^[1]

C₅H₆ + LiC₄H₉ → LiC₅H₅ + C₄H₁₀

Because lithium cyclopentadienide is usually handled as a solution, the solvent-free solid is rarely encountered. According to X-ray crystallography, LiCp is a "polydecker" sandwich complex, consisting of an infinite chain of alternating Li⁺ centers sandwiched between μ-η⁵:η⁵-C₅H₅ ligands.^[2] In the presence of amines or ethers, LiCp gives adducts, e.g. (η⁵-Cp)Li(TMEDA).^[1] LiCp is a common reagent for the preparation of cyclopentadienyl complexes.

See also

• Sodium cyclopentadienide