Uranous oxyfluoride

Uranyl Fluoride, UO Fg, is formed with uranous oxyfluoride (see above) by the action of hydrofluoric acid on urano-uranic oxide Us08-f6HF=U0F2-f2U02F2+3H20. 

The green insoluble uranous oxyfluoride is removed by filtration, and the uranyl fluoride remains as a yellow mass after evaporation of the solution. It is also obtained as a yellow powder by repeated evaporation of uranyl acetate with hydrofluoric acid. A white crystalline form has been described by Smithells, who obtained it by carefully heating the tetrafluoride in air it dissolved in water yielding a yellow solution. 

As mentioned earlier, the two most common and stable types of uranium compounds are those in which uranium is in the tetravalent and hexavalent states. As far as the NFC is concerned, the binary oxides, binary fluorides, and oxyfluorides are of major importance, although several other compounds (e.g., uranyl nitrate, uranyl sulfate, and ammonium uranates) also play a role in the processing and handling of uranium (Table 1.5). Uranium metal and especially uranium alloys also play a significant role in commercial and military applications of uranium. 

---