Nickelocene

• Di (cyclopentadienyl ) nickel
• Bis (cyclopentadienyl ) nickel ( II)

Dark green crystalline solid

Fixed

171-173 ° C

Insoluble in water

Attention

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Nickelocene (di (cyclopentadienyl ) nickel or bis (cyclopentadienyl ) nickel (II)) is a sandwich complex that is an organometallic compound having aromatic ring systems ( metallocene ). Nickelocene is structurally related to the very stable ferrocene, however, contrary to this is not stable in air.

Bonding

Nickelocene is formally composed of a nickel ( II) cation and two cyclopentadienyl anions ( C5H5 ). Generally speaking, therefore an uncharged complex. The binding ratios are similar to those of ferrocene: The cyclopentadienyl anions have as aromatics via a delocalized π -electron system. Each of these two ligands may charge the Ni ( II) cation 6 π - electrons available. The nickel ( II) cation itself has 8 valence electrons, so it still gets 12 electrons from the ligand, so that it has = 20 valence electrons in the complex 8 12. Thus it has two electrons more than after the 18- electron rule would be beneficial, so that these two electrons must occupy an antibonding molecular orbital. This fact also explains the ease of oxidation of nickelocene.

Properties

Nickelocene is a dark green crystalline solid, which is fairly stable in air and can be easily oxidized.

Representation

Can be prepared by various nickelocene Salzmetathesereaktionen for example, sodium cyclopentadienide with nickel ( II) chloride.