Mixed Noble‐Gas Compounds of Krypton(II) and Xenon(VI); [F5Xe(FKrF)AsF6] and [F5Xe(FKrF)2AsF6]

The coordination chemistry of KrF₂ has been limited in contrast with that of XeF₂ , which exhibits a far richer coordination chemistry with main-group and transition-metal cations. In the present work, reactions of [XeF₅ ][AsF₆ ] with KrF₂ in anhydrous HF solvent afforded [F₅ Xe(FKrF)AsF₆ ] and [F₅ Xe(FKrF)₂ AsF₆ ], the first mixed krypton/xenon compounds. X-ray crystal structures and Raman spectra show the KrF₂ ligands and [AsF₆ ]^- anions are F-coordinated to the xenon atoms of the [XeF₅ ]⁺ cations. Quantum-chemical calculations are consistent with essentially noncovalent ligand-xenon bonds that may be described in terms of σ-hole bonding. These complexes significantly extend the XeF₂ -KrF₂ analogy and the limited chemistry of krypton by introducing a new class of coordination compound in which KrF₂ functions as a ligand that coordinates to xenon(VI). The HF solvates, [F₅ Xe(FH)AsF₆ ] and [F₅ Xe(FH)SbF₆ ], are also characterized in this study and they provide rare examples of HF coordinated to xenon(VI).