Abstract Quadratic complete basis set computational studies of singlet and triplet phosphorous cation clusters with hydrides of second and third row elements was presented. This study was performed in order to estimate the stabilities, bond dissociation energies, and energy gaps between singlet and triplet clusters. Structural changes in the course of the complexation, as well as the amount of charge transferred from phosphorus cation to the ligand, was used to assess the stabilities of the complexes (bond dissociation energies) and relative energy gaps. The obtained qualitative results were compared with the energies obtained by this highly accurate ab initio computational methodology. The influence of the nature of these ligands on the stability of these clusters was discussed.