Tetrabutylammonium hexafluorophosphate is a salt with the formula NBu<sub>4</sub>PF<sub>6</sub>. It is a white powder that is used as an electrolyte in nonaqueous electrochemistry. It is highly soluble in polar organic solvents such as acetone and acetonitrile.
The salt consists of a positively charged tetrabutylammonium, a quaternary ammonia cation and a weakly basic hexafluorophosphate anion. These species are chemically inert, which allows the salt to serve as an inert electrolyte over a wide potential range.
This salt can be prepared by the reaction of tetrabutylammonium bromide and potassium hexafluorophosphate in aqueous solution.
Given the sensitivity of electrochemical experiments, this salt is usually further purified, e.g., by recrystallization from aqueous or absolute ethanol.
This salt is used as a supporting electrolyte in electroanalysis as well as electrolytic growth methods (electrocrystallization). For instance, in the presence of this salt, the electrochemical oxidation of tetramethyltetraselenafulvalene (TMTSF) yields single crystals of (TMTSF)<sub>2</sub>PF<sub>6</sub>. This material is the first organic superconductor (T<sub>c</sub> = 0.9 K at 12 kbar) reported by Klaus Bechgaard and Denis Jérome in 1980.