Polymeric binary fluorides

In the preparation of binary fluorides using the general method for the synthesis of polymeric binary fluorides [1] it was noted that when an excess of Lewis acid (beyond the stoichiometric amount) was added to binary fluorides in aHF, a coloured solution resulted without immediate loss of fluorine. This coloured solution contains solvated fluorospecies obtained by the action of excess of Lewis acid on the binary fluoride, probably by removal of F from it. In the case of NiF4 the simplest cationic species would be [NiF3(HF)v]+ [15]. 

Zemva, Bartlett and colleagues reported a general approach to synthesis from HF of polymeric binary fluorides [67] which has a major advantage over many of the synthetic routes used to date. Some of these fluorides are thermodynamically unstable or marginally stable at ambient temperature. Earlier attempts to prepare some of these compounds at elevated temperatures had proved unsuccessful or had led to contaminated products. Some reported synthetic procedures for transition metal tetrafluorides, for example, involving reduction by the metal of the stable pentafluoride at elevated temperature have resulted in products contaminated to greater or lesser extent with the trifluoride or with the metal. 

A General Method for the Synthesis of Polymeric Binary Fluorides Exemplified by AgFa, NiF4, RUF4, and OSF4... 

Fluoride-ion capture from their anion relatives in anhydrous hydrogen fluoride solution by strong fluoride ion acceptors such as AsFb 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. 

A new approach to the synthesis of polymeric binary fluorides has provided Agp3 as a diamagnetic red stdid, isostructural with AUF3. This fluoride was found to oxidize xenon gas spontaneously at 20 °C according to the equation... 

B. Zemva, K. Lutar, A. Jesih, W. J. Casteel, Jr. and N. Bartlett, A General Method for the Synthesis of Polymeric Binary Fluorides Exemplified by AgFa, NiF4, RuF4 and OsF4, J- Chem. Soc. Chem. Comm. (1989) 346-347. 

Figure 12 Binary fluoride and oxide polymers in the mid-region between I and C vertices of a triangle. The bonding in these polymeric regions is more delocalized than either the extreme covalent (O2, F2) or the extreme ionic (NaCl, Cap2)...

CuCl and CuBr can be synthesized by boiling an acidic solution of the halide with an excess of copper metal dilution causes precipitation of white CuCl or pale yellow to white CuBr, which are polymeric even in the vapor state (as a solid, CuCl crystallizes as the zinc blende structure with regular tetrahedral CuCB centers, linked by bridging chlorides). Binary copper compounds with very hard fluoride ligands are not known, undoubtedly because CuF is unstable to disproportionation to form Cup2 and Cu. ... 

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