Silver hexafluorophosphate

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Silver hexafluorophosphate
Identifiers
CAS number	[26042-63-7]
Properties
Molecular formula	AgPF6
Molar mass	252.83 g/mol
Appearance	Off-white powder
Solubility in water	organic solvents
Hazards
MSDS	External MSDS
EU classification	Corrosive (C)
NFPA 704	3
R-phrases	R34
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

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:^[1]

AgPF₆ + Fe(C₅H₅)₂ → Ag + [Fe(C₅H₅)₂]PF₆ E = 0.65 V

[edit] Related reagents

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

[edit] 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.

[edit] References

1. ^ Connelly, N. G. and Geiger, W. E., "Chemical Redox Agents for Organometallic Chemistry", Chem. Rev., 1996, 96, 877-922.doi:10.1021/cr940053x