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

Area of Science:

• Inorganic Chemistry
• Solid-State Chemistry
• Materials Science

Background:

• The first noble-gas compound, xenon hexafluoroplatinate (XePtF₆), has lacked detailed structural characterization since its discovery.
• Understanding the structure of noble-gas compounds is crucial for advancing inorganic chemistry.
• Previous studies on XeF₂-MF₄ systems (M = Cr, Mn) provided foundational data but lacked direct structural links to Pt and Pd analogues.

Purpose of the Study:

• To perform the first successful structural characterization of xenon compounds with platinum and palladium.
• To elucidate the crystal structures of XeF₂·2PtF₄ and XeF₂·2PdF₄.
• To investigate and propose energetically favored structural models for XeF₂·PtF₄ using computational methods.

Main Methods:

• Crystal structure determination using 3D electron diffraction for XeF₂·2PtF₄ and XeF₂·2PdF₄.
• Periodic density functional theory (DFT) calculations to evaluate proposed structural models for XeF₂·PtF₄.
• Comparison with experimentally determined structures of related XeF₂-MF₄ (M = Cr, Mn) compounds.

Main Results:

• The crystal structures of XeF₂·2PtF₄ and XeF₂·2PdF₄ were successfully determined for the first time.
• Both compounds are isostructural with XeF₂·2MnF₄, exhibiting corrugated zigzag double-chain motifs.
• DFT calculations indicated a preference for *cis*-bridging in XeF₂·PtF₄, favoring tetrameric ring and *cis*-chain polymorphs.

Conclusions:

• This study establishes a direct structural relationship between platinum, palladium, and manganese analogues in XeF₂-MF₄ systems.
• The tetrameric ring and *cis*-chain structures are proposed as the most likely models for XeF₂·PtF₄.
• The findings significantly advance the understanding of noble-gas compound structures and reactivity.