Speciation and separation of platinum(iv) polynuclear complexes in concentrated nitric acid solutions.

Understanding the solution chemistry of Pt(iv) is crucial for the hydrometallurgy of precious metals. To gain such an understanding, the speciation and separation of Pt(iv) complexes in concentrated HNO solutions were investigated via Pt L edge X-ray absorption fine structure (XAFS) spectroscopy. The XAFS results for concentrated HNO solutions of NaPt(OH) revealed the dominant presence of Pt polynuclear complexes, wherein the formation of Pt(iv) polynuclear complexes depended on the metal concentration and the NaPt(OH) dissolution temperature.