Crystal Structures of XeF2·2PtF4 and XeF2·2PdF4 Determined by 3D Electron Diffraction and Structural Models of XePtF6

High Resolution Image Download MS PowerPoint Slide 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 6 (XeF 2 ·PtF 4 ), lacks comprehensive structural characterization, and its structure remains to be elucidated. In this study, the XeF 2 –PtF 4 and XeF 2 –PdF 4 systems were reexplored, resulting in the crystal structure determination of XeF 2 ·2PtF 4 and XeF 2 ·2PdF 4 by 3D electron diffraction, marking the first successful structural characterization of compounds from these systems. Both compounds are isostructural with the previously characterized XeF 2 ·2MnF 4, 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 2 ·PtF 4, which were derived from experimentally determined crystal structures of XeF 2 –MF 4 (M = Cr, Mn) analogues. The results reveal a preference for cis -bridging between adjacent platinum(IV) centers and show that a tetrameric ring structure and cis -chain polymorph, modeled after the crystal structure of XeF 2 ·MnF 4 and XeF 2 -deficient 3XeF 2 ·2MnF 4, 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 2 –MF 4 systems and highlight the tetrameric ring structure and cis -chain as likely structural models of XeF 2 ·PtF 4 .