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  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 t2g5eg0 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 : 2PtF5 → PtF4 + PtF6, providing a clear, elegant and straightforward explanation to the thermal instability of PtF5 as consequence of the electronic configuration.