Two alternative interpretations are given for the electronic ground state of bis-eta(8)-annulene[8] cerium, cerocene, based on the same relativistic Douglas-Kroll-Hess complete active space all-electron wave-function. Rotations in the spaces of the one-and many-electron wavefunctions, leaving the total energy invariant, show that the system can be viewed as a complex of a closed-shell Ce(IV) ion sandwiched by two aromatic annulene[8] dianions and bonded with a significant Ce 4f - ring pi covalency, or as a Ce(III) ion with an almost atomic-like 4f(1) subconfiguration, coupled to the unpaired electron in the rings highest energy occupied pi orbitals in a Kondo-type fashion. (C) 2014 Elsevier B. V. All rights reserved.