Oxygen platinum

Platinum reacts with oxygen only at elevated temperatures. Finely divided metal forms platinum oxide, PtO, at about 500°C. When heated at 1,000°C in air or oxygen, platinum loses weight probably due to the evaporation of the thin layer of Pt02 from its surface. 

Schmidt et al. (139) postulated that in the presence of excess oxygen, platinum was transported as volatile oxides through the gas phase and boundary layer. This mechanism could not adequately explain the reconstruction observed far into the excess ammonia regime. It was suggested that under these and other conditions, other volatile platinum species formed. Moreover, these species might decompose by reaction in the boundary layer, leading eventually to the platinum replating itself. 

The Pourbaix diagram for platinum [109] is shown in Fig. 9. The domain of stability of water itself lies between the lower broken diagonal line a (below which water can be reduced to hydrogen) and the upper broken diagonal line b (above which water may be oxidised to oxygen). Platinum metal is stable below the lowest full diagonal line which stands for the reaction... 

As chemically summarised in Fig. 2, the compound behaves as a powerful oxidising agent and as a derivative of platinum(v). Its hydrolysis by water vapour to oxygen, platinum dioxide, and hydrogen hexafluoroplatinate(iv) resembles that of osmium(v), iridium(v), and ruthenium(v) fluoro-salts, which are similarly reduced to the acids of their 4+ ions e.g.,... 

Oxonium fluorination Perchloryl fluoride. Oxygenation Platinum catalyst. Oxymercuration Mercuric acetate. Ozonization Dimethyl sulfide. 

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