Octaisopropylmetallocenes of the lanthanoids Sm (1-Sm), Eu (1-Eu), and Yb (1-Yb) can be obtained easily from the diiodides of the rare earth elements. Like the hexa(tert.-butyl)metallocenes 2-Sm, 2-Eu, and 2-Yb, they show no tendency towards coordination of donor solvent molecules or alkali salts. The decaisopropylmetallocenes 3-Sm, 3-Eu und 3-Yb have been synthesized from the metal and the free pentaisopropylcyclopentadienyl radical. The three europocenes 1-Eu, 2-Eu, and 3-Eu show fluorescence in day-light or under UV irradiation (336 nm). Crystalline 1-Eu and 2-Eu are bent sandwich complexes, whereas for the decaisopropyl derivative 3-Eu axial symmetry with parallel five-membered rings has been observed.