Metal Coordinated HFA Unique Case

From stoichiometric amounts of LaF3 and anhydrous hydrogen fluoride La(HF)2(AsF6)3 was prepared under solvothermal conditions in AsF5 above its critical temperature. The compound crystallizes in space group Pnma (No. 62) with a = 1060.9(2) pm, b = 1726.2(5) pm, c = 770.0(2) pm, and Z = 4 at 293 K. The structure was determined from single-crystal data and shows 10 fluorine atoms connected to the La center. Two of these ligands are provided by HF molecules, a connectivity that was never observed before. All other fluorine ligands are provided by AsF6 units which are bridging between La atoms. In this way infinite slabs are formed which are connected via hydrogen bonds only.