Hartree-Fock (RHF) and second-order Moller-Plesset (MP2) first principles calculations have been performed to study the structures, stabilities, harmonic vibrational frequencies, and bonding properties of MgF2 dimers and trimers, complementing our previous work (J. Phys. Chem. 2001, 105, 4126) on the MgF2 monomer. The less energetic isomers found for (MgF2)(2) and (MgF2)(3) are the bridged F-(Mg2F2)-F (D-2h) and F-MgF2-MgF2Mg-F (D-2d) structures, respectively. A new C-s timer structure has been found and characterized. Correlation energy corrections increase the Mg-F distances by 1.2-1.4% and do not modify appreciably the Mg-F-Mg and F-Mg-F angles. The dissociation energy per MgF2 unit (DE) of (MgF2)(n) increases with n. MP2 frequencies for the (MgF2)(2) D-2h isomer are around 1.0% lower than their RHF equivalents. The whole set of computed frequencies for (MgF2)(n) has allowed us to perform a critical analysis of the experimental vibrational data, where some spectral assignments remained uncertain. The atoms in molecules analysis of the electron density reveals that (MgF2)(n) clustersare highly ionic, with almost nominal net atomic charges (q(Mg) similar or equal to +1.8\e\ and q(F) similar or equal to -0.9\e\). Our previous polarizable-ions model accounts fairly well for the properties of these clusters, rationalizing the energy ordering of trimers in a physically sound way.