  Type Ia supernovae are the outcome of the explosion of a carbon-oxygen white
dwarf in a close binary system. They are thought to be the main contributors to
the galactic nucleosynthesis of iron-peak elements, with important
contributions to the yields of intermediate mass elements. Recent analyses of
the phase diagram of carbon and oxygen containing impurities such as $^{22}$Ne
and $^{56}$Fe in conditions relevant to white dwarf interiors suggest that both
isotopes can partially separate when the temperature of the star is low enough
to start solidifying. The purpose of this paper is to examine the impact of
such a segregation on the yields of the different chemical species synthesized
during explosions. A one-dimensional supernova code has been used to evaluate
the impact of the sedimentation assuming different degrees of chemical
separation. It is found that the main properties of the ejecta, kinetic energy
and ejected mass of $^{56}$Ni do only vary slightly when the separation is
taken into account. However, the yields of important isotopes that are used as
diagnostic tools such as manganese can be strongly modified. Furthermore, the
chemical segregation studied here is able to change several indicators related
to progenitor metallicity (such as the mass ratio of calcium to sulphur in the
ejecta or the UV flux of the supernova) and to its mass, whether it is a
Chandrasekhar-mass white dwarf or a substantially lighter one (such as the
imprint of stable nickel on late-time infrared spectra or those related to the
presence of radioactive nickel at the centre of the ejecta).
