Silver hexafluorophosphate

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CASNo = 26042-63-7
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Section2 = Chembox Properties
Formula = AgPF₆
MolarMass = 252.83 g/mol
Appearance = Off-white powder
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Solubility = organic solvents
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ExternalMSDS = [https://fscimage.fishersci.com/msds/84927.htm External MSDS]
EUClass = Corrosive (C)
NFPA-H = 3
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RPhrases = R34

Silver hexafluorophosphate, commonly referred to "silver PF-6," is an inorganic compound with the formula AgPF₆. This salt is a commonly encountered reagent in inorganic and organometallic chemistry. It is commonly used to replace halide ligands with the weakly-coordinating hexafluorophosphate anion. The abstraction of the halide is driven by the precipitation of the appropriate silver halide. Illustrative is the preparation of acetonitrile complexes from a metal bromide, a reaction that would typically be conducted in a solution of acetonitrile: :AgPF₆ + Re(CO)₅Br + CH₃CN → AgBr + [Re(CO)₅(CH₃CN)] PF₆

As a solution in dichloromethane, AgPF₆ is a very strong oxidant, forming silver metal as a by-product: [Connelly, N. G. and Geiger, W. E., "Chemical Redox Agents for Organometallic Chemistry", Chem. Rev., 1996, 96, 877-922.doi|10.1021/cr940053x] :AgPF₆ + Fe(C₅H₅)₂ → Ag + [Fe(C₅H₅)₂] PF₆ "E" = 0.65 V

Related reagents

In terms of their properties and applications, the tetrafluoroborate AgBF₄ and the hexafluoroantimonate AgSbF₆ are similar to AgPF₆.

Comparison with silver nitrate

Silver nitrate is a traditional and less expensive halide abstraction reagent, as indicated by its widespread use in qualitative tests for halides. Relative to AgPF₆, silver nitrate is poorly soluble in weakly basic solvents, however. More seriously, nitrate is Lewis basic and hence presents an interfering ligand that precludes its use in stringent applications.

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