  The goal of this paper is to investigate properties of clusterized nuclear
matter which is believed to be present in crusts of neutron stars at subnuclear
densities. It is assumed that the whole system can be represented by the set of
Wigner-Seitz cells, each containing a nucleus and an electron background under
the condition of electroneutrality. The nuclear structure calculations are
performed within the relativistic mean-field model with the NL3
parametrization. The first set of calculations is performed assuming the
constant electron background. The evolution of neutron and proton density
distributions was systematically studied along isotopic chains until very
neutron-rich system beyond the neutron dripline. Then we have replaced the
uniform electron background with the realistic electron distributions, obtained
within the Thomas-Fermi approximation in a self-consistent way with the proton
distributions. Finally, we have investigated the evolution of the
$\beta$-stability valley as well as neutron and proton driplines with the
electron density.
