Coordination of KrF2 to a Naked Metal Cation, Mg2+

Abstract Examples of coordination compounds in which KrF 2 functions as a ligand are very rare. In contrast, XeF 2 provides a rich coordination chemistry with a variety of main‐group and transition metal cations. The reactions of Mg(AsF 6 ) 2 and KrF 2 in HF or BrF 5 solvent have afforded [Mg(KrF 2 ) 4 (AsF 6 ) 2 ] and [Mg(KrF 2 ) 4 (AsF 6 ) 2 ]⋅2 BrF 5 , respectively, the first examples of a metal cation ligated by KrF 2 . Their X‐ray crystal structures and Raman spectra show that the KrF 2 ligands and [AsF 6 ] − anions are F‐coordinated to a naked Mg 2+ cation. Quantum‐chemical calculations are consistent with essentially non‐covalent ligand‐metal bonding. These compounds significantly extend the XeF 2 –KrF 2 analogy and the limited chemistry of krypton by introducing a new class of coordination compound in which KrF 2 functions as a ligand towards a naked metal cation.