Thorium fluoride

Complex salts of thorium fluorides have been generated by interaction of ThF with fluoride salts of aLkaU or other univalent cations under molten salt conditions. The general forms of these complexes are [ThF ] [15891 -02-8] ThFJ [1730048-0] and [ThF ] [56141-64-1], where typical countercations are LC, Na", K", Cs", NH" 4, and N2H" 3. Additional information on thorium fluorides can be found in the Hterature (81). 

Jons Jakob Berzelius (1779-1848) discovered Th02 in 1828. The element itself (in impure form) was produced by heating potassium with potassium thorium fluoride. 

Thorium dioxide, 24 761-762 Thorium fluorides, 24 762 Thorium halides, 24 762-763 Thorium hydrides, 24 761 Thorium hydroxide, 24 756 Thorium iodides, 24 763 Thorium isotopes, 24 753-754... 

The fluoride solution is diluted to 100 ml. with water, 8 drops of the indicator are added and the pink coloration just removed with 1/200 hydrochloric acid solution. Then 1 ml. of the monochloroacetate buffer solution is added and the solution is titrated with the thorium nitrate solu -tion to a faint pink coloration. This may be seen more easily by allowing the precipitate of thorium fluoride to settle, when the pink coloration collects at the bottom of the beaker. It is essential to use either bright sunlight or mercury vapour illumination, otherwise the end-point is indistinct. 

Thorium Nitrate, Thorium Fluoride Thorium Thorium Dioxide Tetrahydrate Tetrahydrate Carbonate... 

Potassium fluoride solution bulky, white precipitate of thorium fluoride, ThF4, insoluble in excess of the reagent (distinction and method of separation for aluminium, beryllium, zirconium, and titanium). 

Thorium fluoride helps produce the bright beam used in searchlights, such as those being used to illuminate this historical landmark. IMAGE COPYRIGHT 2009, PHILIP LANGE. USED UNDER LICENSE FROM SHUTTERSTOCK.COM. 

Thorium fluoride is used in the manufacture of propane lantern mantles and high-intensity searchlights. 

The separation of Th as the sparingly soluble thorium fluoride is equally selective [4]. The solubility of ThF4 is lower than that of the oxalate. Usually, the sample solution in hydrofluoric acid is evaporated to a small volume and diluted with water to precipitate Th, U(IV), and rare-earth metals. La, Ce, or Ca are used as collectors for traces of Th. Since the fluoride precipitate is difficult to filter off, centrifugation is advisable. 

Zirconium may lie removed hy fusing the oxides with KIlFj and extracting with water acidified with UK. The zirconium dissolves, forming K-ZrK, hut both < [Pg.167]

Hydrated thorium fluoride is precipitated when a soluble fluoride is added to a solution of thorium nitrate. Precipitation can be prevented by addition of aluminum nitrate to complex the fluoride ion, an expedient used in the Thorex process (Chap. 10, Sec. 5). 

Electrolysis of fused salts. The first electrolytic processes used thorium fluorides, as these are less hygroscopic than thorium chloride. In a process developed for the U.S. AEC fS3], a solution of dried 15 to 20% KThFs in molten sodium chloride was electrolyzed at 800 to 900°C in a graphite anodic cell with a molybdenum cathode under an inert argon atmosphere. As only chlorine was produced at the anode, fluorides accumulated in the electrolyte and required its periodic renewal. A somewhat similar process, involving electrolysis of Thp4 in molten KCl/NaCl has been used in the Soviet Union [Kl]. 

VIII. 1 Fluorine compounds and complexes VIILl.l Solid and gaseous thorium fluorides VIILl.1.1 ThF(g), ThF Cg), ThFjCg)... 

VIII.1.2.1 Formation constants of thorium fluoride complexes, ThF "... 

Table VIII-8 SIT ion-interaction parameters nsed by this review in developing the thorium-fluoride system model.

VIILl.2.3 Summary of selected values for the aqueous thorium fluoride species ... 

VIII.1.3 Other solid thorium fluoride compounds... 

This study was not conducted at a fixed ionic strength, so evidence for the equilibrium with the solid phase is lacking. As the reported values for the solubility product of ThF4(cr, hyd) vary by 1.5 orders of magnitude, and values of thorium fluoride and hydrolysis constants from different chemical systems and ionic strengths were combined, this review does not consider the calculated solubility product (4.5 x 10 (mol L ) ) to be reliable. 

M NH4NO3 with the total ionic strength maintained at (0.01 + 0.001) M. The experiments are described in detail, and the response of the fluoride electrode in different solutions and at different temperatures is discussed. Thorium fluoride equilibrium data (free fluoride molar concentrations and total molar concentrations of fluoride, hydrogen, and thorium) at 5, 25, and 45°C are presented in tabular form. 

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