Hexafluorophosphoric acid refers to a family of

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

s produced by combining phosphorus pentafluoride and

hydrofluoric acid Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colorless, acidic and highly corrosive. A common concentration is 49% (48–52%) but there are also stronger solutions (e.g. 70%) and pure HF has a boiling p ...

. The idealized

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

for hexafluorophosphoric acid is , which also is written . Hexafluorophosphoric acid is only stable in solution, decomposing to HF and PF₅ when dry. It exothermically reacts with water to produce oxonium hexafluorophosphate () and hydrofluoric acid. Additionally, such solutions often contain products derived from hydrolysis of the P-F bonds, including , , and , and their conjugate bases. Hexafluorophosphoric acid attacks glass. Upon heating, it decomposes to generate HF. Crystalline has been obtained as the hexahydrate, wherein is enclosed in truncated octahedral cages defined by the water and protons.

NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic f ...

indicates that solutions derived from this hexahydrate contain significant amounts of HF. Whereas a species with the formula HPF₆ remains unknown, the analogous molecular hexafluoroarsenic acid (HAsF₆) has been crystallized.

References

{{Hexafluorophosphates Hexafluorophosphates Mineral acids

See also

References