Contribution of X-ray Spectroscopy to Mineralogy: Exploring Platinum Using High-Energy Resolution Fluorescence Detection X-ray Absorption Spectroscopy, HERFD-XAS

Samples analyzed here included Pt0 (TR), PtIIS (HR), PtIVS2 (TR), K2PtIICl4 (HR+TR), K2PtIVCl6 (HR+TR), PtIVO2 (HR+TR), C6H12N2O4PtII (HR+TR), and aqueous solutions of K2PtIICl4 and H2PtIVCl6 (NR+TR), as well as (NH4)2PtIV(S5)3 (HR+TR). XANES spectra in HERFD mode offer a better energy resolution than in conventional modes, allowing a more accurate identification of Pt redox state and coordination geometry. EXAFS spectra in all three modes for a given com-pound yield identical within errors values of Pt-neighbor interatomic distances and mean square relative displacement (MSRD, σ²) parameters. In contrast, both TR and NR spectra on one hand and HR spectra on the other hand yield distinct amplitude reduction factor (S02) values, 0.76 ± 0.04 and 0.99 ± 0.07 (1 standard error), respectively. This study contributes to the development of an open-access XAS database SSHADE.