Rate coefficients have been measured over the temperature range 300-550 K for the reactions of Ar+ with PF5, PF3, and NF3, using a flowing-afterglow apparatus. The rate coefficients were found to be either collisional in magnitude or nearly so, and independent of temperature within experimental uncertainty. These reactions proceed by dissociative charge transfer, releasing F atoms. The ionic products of Ar+ reactions are PF4+ from PF5, PF2+ from PF3, and NF2+ from NF3. He+ was observed to react rapidly with PF5, PF3, and NF3.