  While the effect of relativity in the electronic density has been widely
studied, the effect on the pair probability, intracule, and extracule densities
has not been studied before. Thus, in this work, we unveil new insights related
to changes on the electronic structure caused by relativistic effects. Our
numerical results suggest that the mean inter-electronic distance is reduced
(mostly) due to scalar-relativistic effects. As a consequence, an increase of
the electron-electron repulsion energy is observed. Preliminary results suggest
that this observation is also valid when electronic correlation effects are
considered.
