With respect to the ionizable fluoride salt MF wherein M is a member selected from the group consisting of potassium, cesium, silver, rubidium and tetraalkyl ammonium ions; potassium and cesium are preferred embodiments, potassium being most preferred. 8 constant agitation 76.7 grams (0.46 mol) of gaseous hexafluoroacetone were introduced through the gas inlet tube over a period of 2 hours.