Arsenic oxide fluorides preparation

Arsenic(III) fluoride is prepared by reacting arsenic(III) oxide with hydrogen fluoride, with calcium fluoride and sulfuric acid, or with fluorosulfonic acid.12... 

Although Moissan prepared arsenic (III) fluoride by the action of fluorine on arsenic and on arsenic (III) chloride,1 the only convenient laboratory procedure involves distillation of a mixture of arsenic (III) oxide, calcium fluoride, and concentrated sulfuric acid.2 University of Illinois, Urbana, Bl. t University of Michigan, Ann Arbor, Mich. 

As the cofacial dimer 1 is a readily available compound, the best method for the preparation of thiatriazinium salts is to treat 1 with nitrosyl tetrafluoroborate or hexafluorophosphate. The reaction mixture must be kept under inert gas during the evolution of nitrogen oxide. A direct method is the reaction of 1-fluorothiatriazines, e.g. 3, with arsenic(V) fluoride or phosphorus pentafluoride. The so-called silver salt method consists of the reaction of 1-chlorothia-triazincs with silver(I) hexafluoroarsenate in liquid sulfur dioxide. 

The heavier phosphorus trihaUdes (PX3, X = Cl, Br, I) are prepared by direct halogenation. The trifluoride, on the other hand, is best synthesized by treating the trichloride with an ionic fluoride such as CaF2 or ZnF2- The arsenic, antimony, and bismuth trifluorides are prepared by adding hydrogen fluoride to the oxides. (If fluorine gas is used, the pentafluorides result.) The other trihalides of arsenic and antimony can be produced by direct halogenation of either the elements or the trioxides, while the bismuth trihalides are best produced by the action of aqueous hydrohalic acids on 61203. 

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