It is an alkali halide salt and occurs naturally as the rare mineral carobbiite.

Solutions of KF will etch glass due to the formation of soluble fluorosilicates, although HF is more effective.

[4] In organic chemistry, KF can be used for the conversion of chlorocarbons into fluorocarbons, via the Finkelstein (alkyl halides)[5] and Halex reactions (aryl chlorides).

[6] More efficient fluorination of aliphatic halides can be achieved with a combination of crown ether and bulky diols in acetonitrile solvent.

[8] Like other sources of the fluoride ion, F−, KF is poisonous, although lethal doses approach gram levels for humans.