The anion is prepared by treatment of phosphorus pentachloride with tetrachlorocatechol followed by a tertiary amine gives the anion:
:PCl  +  3 CCl(OH)   →   H[P(OCCl)]  +  5 HCl
:H[P(OCCl)]  +  BuN   →   BuNH [P(OCCl)]
Using a chiral amine, the anion can be readily resolved.