2PCl5 + 2AsF3 → (PCl4)[PF6] + 2AsCl3
Phosphorus(V) chloride react with arsenic(III) fluoride to produce tetrachloridophosphorus(V) hexafluorophosphate(V) and arsenic(III) chloride. The reaction is conducted in a liquid chloride arsenic(III), at a temperature near 0°C.