The orange precipitate obtained after the well-known preparation of fl
uorenyllithium was recrystallized from a solution of benzene or toluen
e in order to get orange-red crystals which were of sufficient quality
for X-ray diffraction. By this procedure we succeeded in redeterminin
g the molecular structure of a donor-free unsubstituted fluorenyllithi
um compound, which might be the smallest alkali-metal compound contain
ing a donor-free cyclopentadienyl-like ligand within an annelated ring
system to date. The description of the bonding situation is based on
ab initio calculations as well as on a comparison with analogous compo
unds.