Room temperature preparations of second and third transition series tetrafluorides and a possible novel structure type for OsF 4 and RhF 4

Abstract

The polymeric tetrafluorides, MF 4 (M=Mo, Ru, Pd, Re, and Os) have been precipitated from their MF 6 2− salts in liquid anhydrous hydrogen fluoride (aHF) at ∼20 °C. For M=Ru, Os and Pd, AsF 5 can be used to displace the tetrafluoride, but this strong F − acceptor is too strongly oxidizing for use in making MoF 4 and ReF 4, for which SbF 5 is effective. X-ray powder diffraction photograph (XRDP) show the MF 4 to have the same structures as those from higher temperature preparations, when previously known. XRDP of OsF 4 are very like those of RhF 4 and indicate a close structural relationship of the pair, and a significant structural difference from the PdF 4 type structure adopted by M=Pd, Pt, Ir, and Re. A new, two-dimensional, ‘raft’ structure is proposed for OsF 4 and RhF 4.