THE CHEMISTRY OF URANIUM FLUORIDES

The preparation of UF3 by reduction with H2 or Al is described. The lattice parameters and chemical properties of UF3 are summarized. Three general methods of preparing UF4 are presented. UF4 can be precipitated from aqueous solution by electrolysis or by using a reducing agent such as SnCl2, CuCl, or SO2 plus HCOOH in the presence of HF or NH4F. The second type of method depends on the fluorination of UO2 with HF at high temperature or the direct fluorination of UO2 with various freons.'' The third type of method depends on the reduction of UF6 by H2, gaseous HCl, HBr or HI, or by reduction with CCl4. Data on the crystal hydrated, lattice parameters, vapor pressure, heat capacity, enthalpy and entropy of UF4 are presented. The reactions of UF4 with H2 O, O2, ClF3 and BrF3, and the reduction of UF4 with Mg to U are summarized. Phase diagrams are presented for the systems LiF - UF4 ,, NaF UF4, and NaF - ZrF4- UF4. The preparation and thermodynamic properties of intermediate fluorides such as UF5, U2F9, and U4F17 are given. Methods of modynamic properties and chemical reactions of UF6 are summarized. The properties of UO2F2 are described.