Noun
cyclopentadienyl (plural cyclopentadienyls)
(organic chemistry) The univalent anion derived from cyclopentadiene; contains a ring of delocalized electrons; forms metallocene compounds with transition metals.
According to the IUPAC definition, a metallocene contains a transition metal and two cyclopentadienyl ligands coordinated in a sandwich structure, i.e., the two cyclopentadienyl anions are on parallel planes with equal bond lengths and strengths. Source: Internet
Ansa-metallocenes are derivatives of metallocenes with an intramolecular bridge between the two cyclopentadienyl rings. Source: Internet
In the structure shown at right, the two pentagons are the cyclopentadienyl anions with circles inside them indicating they are aromatically stabilized. Source: Internet
Like indium, thallium cyclopentadienyl compounds contain thallium(I), in contrast to gallium(III). Source: Internet
Organoberkelium compounds Berkelium forms a trigonal (η 5 –C 5 H 5 ) 3 Bk metallocene complex with three cyclopentadienyl rings, which can be synthesized by reacting berkelium(III) chloride with the molten beryllocene ( Be (C 5 H 5 ) 2 ) at about 70 °C. Source: Internet
In metallocenes of the type (C 5 R 5 ) 2 M, the cyclopentadienyl rings rotate with very low barriers. Source: Internet