  The question of classicality is addressed in relation with the shape of the
nuclear skeleton of molecular systems. As the most natural environment, the
electrons of the molecule are considered as continuously monitoring agents for
the nuclei. For this picture, an elementary formalism of decoherence theory is
developed and numerical results are presented for few-particle systems. The
numerical examples suggest that the electron-nucleus Coulomb interaction is
sufficient for inducing a blurred shape with strong quantum coherences in
compounds of the lightest elements, H$_2$, D$_2$, T$_2$, and HeH$^+$.
