A molecular orbital study via the QR-SCMEH-MO (quasirelativistic self consistent modified extended Hu †ckel molecular orbital) method has been carried out on the unusual Pt 5coordinated complex Pt (SnCl 3 ) 3À 5 . The computed UV-Visible spectral data and NMR parameters are found to be in good agreement with the reported experimental values. In addition, the magnetic susceptibility and PtASn bond energy have been calculated, although there are no reported experimental data with which to compare these results. PtASn bond energies of other Pt-SnX 3 (X ¼ Cl, Br) systems and are compared with proposed bond energy trends based on NMR and observed bond distances.