A Homoleptic KrF Complex, [Hg(KrF ) ][AsF ] ⋅2 HF.

The reaction of Hg(AsF ) with a large molar excess of KrF in anhydrous HF has afforded the first homoleptic KrF coordination complex of a metal cation, [Hg(KrF ) ][AsF ] ⋅2 HF. The [Hg(KrF ) ] dication is well-isolated in the low-temperature crystal structure of its HF-solvated [AsF ] salt, and consists of eight KrF molecules that are terminally coordinated to Hg by means of Hg-F(KrF) bonds to form a slightly distorted, square-antiprismatic coordination sphere around mercury. The Raman spectrum of [Hg(KrF ) ] was assigned with the aid of calculated gas-phase vibrational frequencies. Computational studies indicate that both electrostatic and orbital interactions are important for metal-ligand bonding and provide insight into the geometry of the [Hg(KrF ) ] cation and the nature of noble-gas difluoride ligand bonding.