BiFluorides-TriFluorides

Ammonium Polyfluoride, CAS 7664-39-3/1341-49-7, is a blended fluoride that has the formula (NH₄)HF₂ + HF.  Ammonium Polyfluoride is 80% HF Acid and 20% Ammonium BiFluoride.  It is used for pickling of steels and others metals and for general surface treatment in the metals industry, as an additive in crude oil drilling, as a polishing additive in the aluminum industry, as a polishing, frosting, and etching additive in the glass, ceramic, and porcelain industries, and as a general cleaning additive for aluminum parts cleaners as well as textile cleaning and industrial laundry souring.

Potassium Bifluoride, CAS 7789-29-9, has the formula KHF₂.  Potassium Bifluoride is used in metal fluxes and silver solder fluxes, in Fluorine cell electrolyte, as a polymerization catalyst, and in the induction of fluorine in organic synthesis.