Calculations for compounds (1-6) of models M₂X₂ ( M = Ag, Cu; X = Cl, Br, I ) were performed at HF, MP2 and DFT levels with different basis sets. Geometry optimisations were then performed, and the results were compared with a statistical summary of X-ray values. Using the same procedure, calculations on the experimental related compounds [Ag₂Br₂](PH₃)₃ and [Cu₂Cl₂](PH₃)₂ (7-8) were done and the theoretical structures were compared with the experimental ones. Theoretical studies of the charge density were also conducted in order to analyse the structure and the possible bonding nature of the Metal-Metal and Metal-Ligand interaction. No M···M interaction was found for the experimentally related compounds 7 and 8.