Crystal Structures of XeF·2PtF and XeF·2PdF Determined by 3D Electron Diffraction and Structural Models of XePtF.

Although the demonstration of noble-gas reactivity represents one of the most significant breakthroughs of 20th-century inorganic chemistry, the first noble-gas compound, XePtF (XeF·PtF), lacks comprehensive structural characterization, and its structure remains to be elucidated. In this study, the XeF-PtF and XeF-PdF systems were reexplored, resulting in the crystal structure determination of XeF·2PtF and XeF·2PdF by 3D electron diffraction, marking the first successful structural characterization of compounds from these systems. Both compounds are isostructural with the previously characterized XeF·2MnF, featuring corrugated zigzag double-chain motifs formed by interconnected octahedral fluoridometallate(IV) units. Periodic density functional theory calculations were employed to evaluate the structural models of XeF·PtF, which were derived from experimentally determined crystal structures of XeF-MF (M = Cr, Mn) analogues. The results reveal a preference for -bridging between adjacent platinum(IV) centers and show that a tetrameric ring structure and -chain polymorph, modeled after the crystal structure of XeF·MnF and XeF-deficient 3XeF·2MnF, respectively, emerge as energetically favored. The results of this study thus provide a direct structural link between platinum, palladium, and manganese analogues in the XeF-MF systems and highlight the tetrameric ring structure and -chain as likely structural models of XeF·PtF.