The first observation of the [Cp3Mn]- anion; structures of hexagonal [(eta 2-Cp)3MnK.1.5thf] and ion-separated [(eta 2-Cp)3Mn]2[Mg(thf)6].2thf.

Hexagonal [(eta 2-Cp)3MnK.1.5thf] 1 and ion-separated [(eta 2-Cp)3Mn]2[Mg(thf)6].2thf 2 are obtained from reactions of CpK and Cp2Mg, respectively, with manganocene, Cp2Mn; they are the first complexes to be structurally characterised containing the [Cp3Mn]- anion.