Ab initio methods have applied to HgI2, PtI2, and PbI2 to assess the performance of relativistic effective core potentials (RECPs) on ground-state properties of heavy-metal iodides. With electron correlation included via Moller-Plesset (MP) theory up to third order, good agreement with experiment was found for the mercury and lead compounds. PtI2 is also bent in its ground state, with a bond angle near to 96 degrees. In terms of bond strength, the following order was found (most stable first) : Pb-I > Pt-I > Hg-I. Harmonic vibrational frequencies and ionization potentials are also reported. The direction of the first nonzero moment indicates that the metal atom is effectively positively charged in all three molecules. In HgI2, fourth-order MP corrections are shown to be unimportant.