  We report theoretical and numerical evaluations of the phase diagram for
patchy colloidal particles of new generation. We show that the reduction of the
number of bonded nearest neighbours offers the possibility of generating liquid
states (i.e. states with temperature $T$ lower than the liquid-gas critical
temperature) with a vanishing occupied packing fraction ($\phi$), a case which
can not be realized with spherically interacting particles. Theoretical results
suggest that such reduction is accompanied by an increase of the region of
stability of the liquid phase in the ($T$-$\phi$) plane, possibly favoring the
establishment of homogeneous disordered materials at small $\phi$, i.e. stable
equilibrium gels.
