William J. Casteel

Some chemistry of high oxidation state transition metal fluorides in anhydrous HF

Abstract The salt AgFIrF6 ( AgIrF 6 + 1 2 F 2 in AHF) is isostructural with AgFAsF6. Failure to prepare AgFOsF6 (AgOsF6 + F2 → AgF2 + OsF6) indicates that the one-dimensional chain cation (AgF)nn+ takes the electron from OsF6−. The Ag(solv)2+ ion oxidizes IrF6− to IrF6 and at −78 °C in AHF, O2 to O2+ (O2 + Ag2+ + 2AsF6− → O2+AsF6− + AgAsF6). This reaction is negligible at ∼20 °C because of the loss of translational entropy that accompanies the formation of the crystalline products. Dissolution of AgF3 in AHF with A (A = AsF5, SbF5 or BiF5) gives a solution {Ag(solv)III} which oxidizes PtF6− or RuF6− to MF6 and O2 to O2+. K2NiF6 in AHF below −60 °C with greater than threefold molar excess of BF3 yields yellow-brown solutions {Ni(solv)IV} which also oxidize PtF6− or RuF6− to MF6. The species Ag(solv)III and Ni(solv)IV in AHF are oxidizers of unsurpassed power.

Room temperature preparations of second and third transition series tetrafluorides and a possible novel structure type for OsF4 and RhF4

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 ∼20xa0°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 .

A general method for the synthesis of polymeric binary flurides exemplified by AgF3, NiF4, RuF4, and OsF4

Fluride-ion capture from their anion relatives in anhydrous hydrogen fluoride solution by strong fluoride ion acceptors such as AsF5 provides a general approach to the synthesis of polymeric binary fluorides and is particularly advantageous in the synthesis of highest-oxidation-state transition metal polymeric fluorides.

Syntheses and some properties of binary fluorides of silver, copper and nickel

Abstract Thermally unstable highest-oxidation-state transition metal polymeric fluorides (e.g. AgF 3 , NiF 4 ) are precipitated from anhydrous hydrogen fluoride (AHF) solutions of their salts by addition of fluoroacids (A) such as BF 3 , PF 5 or AsF 5 [1]: MF x y− + yA → MF (x−y) + yAF − . Red, diamagnetic AgF 3 precipitated by AsF 5 from AHF solutions of AgF 4 − salts is reduced with excess of AsF 5 by following equation: AgF 3 + AsF 5 → AgFAsF 6 + 1/2F 2 . While such reduction does not occur with BF 3 this acid is therefore preferred for the preparation of stoichiometric AgF 3 . Silver trifluoride is thermodinamically unstable and loses F 2 in contact with AHF according to the equation: 3AgF 3 → Ag 3 F 8 + 1/2F 2 . The formation of Ag 3 F 8 by the interaction of one mole of Ag(II) and two moles of Ag(III) confirmed that the material formed in the degradation of AgF 3 is a mixed valence material Ag(II)Ag(III) 2 F 8 . Interaction of AgF + with AuF 4 − (1:1) in AHF yields maroon Ag(II)Ag(III)F 5 . Silver trifluoride is isostructural with AuF 3 . Its powerful oxidizing properties are in accord with the tight binding of its valence shell d orbital electrons. CuF 6 3− salts interact quantitavely with liquid AHF already at −60° yielding bright red CuF 3 : CuF 6 3− + 3xHF → CuF 3 + 3F(HF) x − . The oxidizing properties of above-mentioned fluorides will be discussed.