Lithium cyclopentadienide
Other names
lithium cyclopentadienylide, cyclopentadienyllithium, LiCp
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Molar mass 72.04 g·mol−1
Appearance colorless solid
Density 1.064 g/cm3
Solubility THF, dimethoxyethane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.

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


  1. ^ a b Reent Michel; Regine Herbst-Irmer; Dietmar Stalke (2011). "Revealing Coordination Patterns in C5-Cyclic Lithium Organics". Organometallics. 30 (16): 4379–4386. doi:10.1021/om200471e.
  2. ^ Robert E. Dinnebier; Ulrich Behrens & Falk Olbrich (1997). "Solid State Structures of Cyclopentadienyllithium, -sodium, and -potassium. Determination by High-Resolution Powder Diffraction". Organometallics. 16 (17): 3855–3858. doi:10.1021/om9700122.