Ammonium hexafluorophosphate explained

Ammonium hexafluorophosphate is the inorganic compound with the formula NH₄PF₆. It is a white water-soluble, hygroscopic solid. The compound is a salt consisting of the ammonium cation and hexafluorophosphate anion. It is commonly used as a source of the hexafluorophosphate anion, a weakly coordinating anion. It is prepared by combining neat ammonium fluoride and phosphorus pentachloride. Alternatively it can also be produced from phosphonitrilic chloride:^[1]

PCl₅ + 6 NH₄F → NH₄PF₆ + 5 NH₄Cl

PNCl₂ + 6 HF → NH₄PF₆ + 2 HCl

References

1. Book: W. Kwasnik. Ammonium Hexafluorophosphate (V). Handbook of Preparative Inorganic Chemistry, 2nd Ed. . G. Brauer. Academic Press. 1963. NY, NY. 1. 195–196.