Quantum chemical study of PtFn and PtCln (n = 1–6) complexes: An investigation of superhalogen properties

Quantum chemical calculations using gradient corrected density functional theory reveals the unusual properties of a platinum (Pt) atom interacting with fluorine (F) and chlorine (Cl) atoms. Up to six F and Cl atoms are bound to a single Pt atom, which results in increase of electron affinities as successive halogen atoms are attached reaching a peak value of 8.05 eV for PtF6 and 6.46 eV for PtCl6. The large HOMO–LUMO energy gap, both in neutral and anionic forms, reveals further evidence of their stability. The unusual properties bring about the involvement of inner shell 5d-electrons, which not only allow PtFn and PtCln (n = 1–6) complexes to belong to the class of superhalogens but also show that its valence can exceed the nominal value of 1.