Cyclopentadienyl complex
A cyclopentadienyl complex is a coordination complex of a metal and cyclopentadienyl groups (C
5H−
5, abbreviated as Cp−). Cyclopentadienyl ligands almost invariably bind to metals as a pentahapto (η5-) bonding mode.  The metal–cyclopentadienyl interaction is typically drawn as a single line from the metal center to the center of the Cp ring.