Relativistic contribution: an electronic explanation to the thermal disproportionation of PtF5

In the present work, is performed a computational thermochemical study of platinum tetrafluoride (PtF₄) and platinum pentafluoride (PtF₅). The results are compared to those previously [1] obtained to PtF₆ as well as experimental data. Is concluded that in gaseous phase PtF₄ and PtF₅ retain their structures and number of unpaired electrons exhibited in the solid phase. Furthermore, is proposed that the generally accepted t_2g⁵e_g⁰ configuration to Pt⁵⁺ is not correct. Based on the calculated results, an energy diagram is proposed to PtF₅, which explain why, upon heating, platinum pentafluoride disproportionates readily [7]: 2PtF₅ → PtF₄ + PtF₆, providing a clear, elegant and straightforward explanation to the thermal instability of PtF₅ as consequence of the electronic configuration.