We investigate the valence electronic charge density of the C-60(-) monomers in (C-60(-))(n) polymer chains in K- and RbC60 by means of a nonorthogonal tight-binding formalism using experimental data on the positions of the carbon atoms. Various configurations of the C-60 cages are considered. Starting from the ideal icosahedral C-60 structure and moving to the realistic, experimentally determined spatial configuration of the C-60 cages in K- and RbC60, we observe a systematic increase of the electric quadrupole moments on the C-60(-) monomers. We also confirm the validity of factorizing the charge density of a C-60(-) monomer into an angular and a radial part. (C) 2004 American Institute of Physics.