The molecular structure of dicyclopentadienylzinc (zincocene) determined by gas electron diffraction and density functional theory calculations: η5,η5, η3,η3 or η5,η1 coordination of the ligand rings?

Structure refinements to gas electron diffraction data and density functional theory calculations at the B3LYP/LanL2DZ level show that dicyclopentadienylzinc, Cp2Zn, has an η5,η1 slip sandwich molecular structure in the gas phase.