From organic hypofluorites

Perfluoroalkoxide ions are postulated as intermediates in the mechanism leading to the hypohahtes from acid fluorides. Generally, organic hypofluorites can be prepared from acid fluorides by the action of metal fluorides and elemental flnorine... 

The white cesium fluoroxy sulfate precipitates from the reaction medium and may be kept for several months in the cold (0 to -15 °C) Metal surfaces can cause detonation of the reagent. The reaction scope of cesium fluoroxysulfate seems narrower than that of acetyl hypofluorite because of its limited solubility in organic solvents Cesium fluoroxysulfate has not been prepared with a fluorine-18 label. 

C1F 54.46 - 155.6/- 100.1 + + + + also usable for synthesis of hypofluorites and oxidative S- or Se-fluorinations of organic sulfur and selenium compounds, frequently in situ preparation of the agent from A -chloro-substituted amides and HF, HF-containing systems or AgF 4, 7... 

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