Ammonium difluorophosphate

In some cases the use of ammonium difluorophosphate is suitable. The reaction is then performed in ethereal solution, from which the unsoluble ammonium chloride can be separated by filtration ... 

The ammonium difluorophosphate which is better soluble in ethanol is separated by extraction with this solvent 34). The reactions (22) 54) and (23) (55) which are run at higher temperatures do not give purer products ... 

Phosphorus pentoxide (23.5 g.) is heated with 185 g. of NI jF in a 300-ml. nickel or copper crucible until the reaction starts. It progresses by itself, but the mixture should be well stirred. After cooling, the mass is pulverized and boiled in a glass flask with 600 ml. of absolute alcohol. The mixture is filtered hot through a fluted filter the filtrate is immediately cooled and neutralized with ammoniacal alcohol. Ammonium difluorophosphate(V) (8.3 g.) separates out and is removed filtration. The filtrate is evaporated to dryness in a platinum dish on a water bath. The yield is 11.6 g. (70% of theoretical) of crude salt. This NH4P03Fa is still contaminated with NH F but is suitable for many purposes. 

Difluorophosphates. Difluorophosphates have limited appHcations largely because of hydrolytic instabiHty of the P03F 2 ion. The ammonium salt can be prepared from ammonium fluoride and phosphoric anhydride. 

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