Solid zirconium fluorides

Use may be made of the fact that even solid calcium fluoride reacts with the zirconium-alizarin-S reagent (compare Section IV. 17, reaction 6) and, in consequence, the fluoride test may be carried out in the presence of oxalate and phosphate, which interfere in aqueous solution. The calcium salts are precipitated in neutral or faintly basic solution. The precipitate is ignited and digested with dilute acid. The residue is then tested for fluoride by the zirconium-alizarin-S test the red hue of the reagent disappears and a yellow colouration results (see Section IV.17, reaction 6). 

Aflammit ZR Dipotassium hexafluorozirconate(2-) Dipotassium zirconium hexafluoride EINECS 240-985-6 HSDB 2019 NSC 310011 Potassium fluorozirconate Potassium fluorozirconate (K2ZrF6) Potassium hexafluorozirconate Potassium zirconifluoride Potassium zirconium fluoride Potassium zirconium hexafluoride Zirconate(2-), hexafluoro-, dipotassium Zirconium potassium fluoride, Flameprooflng agent used in wool processing. Also used in manufacture of zirconium. Solid slightly soluble in cold H2O, Thor Chemicals (UK) Ltd. 

EINECS 232-018-1 Zirconium fluoride Zirconium fluoride (ZrF4), (P4)- Zirconium tetrafluoride. Component of molten salts used in nuclear reactors. Solid mp = 640° bp = 905° d o4.6 LDso (mus orl) = 98 mg/kg. Atomergic Chemetals Cerac ElfAtochem N. Am. 

Zirconium tetrachloride solid. SeeZirconium tetrachloride Zirconium tetrafluoride CAS 7783-64-4 EINECS/ELINCS 232-018-1 Synonyms Zirconium fluoride Zirconium (IV) fluoride Empirical F r Formula Zrp4... 

The fact that solid calcium fluoride reacts immediately with zirconium alizarinate renders it possible to detect fluoride in a mixture with phosphates and oxalates. These salts interfere with the detection of fluoride in aqueous solution, because they form either insoluble or complex zirconium phosphates (or oxalates) and thus destroy the red zirconium-alizarin compound and also produce the yellow color. The fluoride in such mixtures may be isolated by treating the alkaline or neutral test solution with calcium chloride the precipitate is ignited and digested with dilute acid. The residue then may easily be tested for fluoride by the zirconium-alizarin solution. ... 

Dejneka M., Snitzer E., Riman R.E. Spectroscopic characterization of Eu " "-doped inorganic and alkoxide sol-gel derived fluorozirconate glass and zirconium fluoride gels. J. Non-Cryst. Solids... 

Using the solid zirconium selenite, labelled with Se by reactor irradiation, trace fluoride ion may be determinedusing the reaction ... 

Mix together on a spot plate 2 drops each (equal volumes) of a 0-1 per cent aqueous solution of alizarin-S (sodium alizarin sulphonate) and zirconyl chloride solution (0-1 g solid zirconyl chloride dissolved in 20 ml concentrated hydrochloric acid and diluted to 100 ml with water) upon the addition of a drop or two of the fluoride solution the zirconium lake is decolourized to a clear yellow solution. 

Typical physical, chemical, and radiochemical properties of calcined solids from acid aluminum waste and fluoride-bearing zirconium waste are given in Table V. Other components in the calcine, e.g., actinide elements, can be calculated on the basis of the analyses of the liquid waste. 

Fractional crystallization of the double potassium fluorides was the method originally used to separate hafnium from zirconium. Because these salts form solid solutions and the ratio of solubilities is close to unity (1.54 at 20°C), multiple recrystallizations are necessary for the necessary completeness of separation. In the United States, Kawecki [Kl] has found that 10 recrystaUizations of the double potassium fluorides reduced the hafnium content of zirconium from 2.0 to 0.1 percent. 

The vapor pressures above solid a- (201) and /S-zirconium tetra-fluoride (16) are described by the equations in Table XXIII over the temperature ranges specified. The calculated heat of sublimation for the tetrafluoride of zirconium is some 20 kcal/mole greater than the heats of sublimation of the other tetrahalides of zirconium (Table XXIII), which is consistent with the greater complexity of the fluoride solid state compared to the probable structures of the other halides in the solid state. Zirconium tetrafluoride in the gaseous state is known to be monomeric by mass spectroscopy (96). Fluorine bomb calorimetry (223, 224) has been used to determine the standard heats of formation of the tetra-fluorides ZrF4, —456.80 0.25 kcal and HfF4, —461.40 0.85 kcal. 

Zirconium and hafnium form halides of composition MX4 and also MX3, MX2, and MCI (see below) see Fluorides Solid-state Chemistry Haiides Soiid-state Chemistif). 

Titanium fluoride melts at 400° C. under pressure and sublimes at 284° C. This property would suggest its reduction with sodium by the method now used for the production of zirconium—i.e., gas phase reduction (42), However, the sodium fluoride produced melts at 988° C. or 108° C. above the boiling point of sodium, and solid crusts of sodium fluoride might surround the reducing agent. At this temperature iron would also react with the titanium obtained. This eliminates the sodium reduction of the fluoride at atmospheric pressure, but bomb reduction might work especially after addition of zinc fluoride as indicated by Spedding (57, 83) for the reduction of zirconium tetrafluoride with calcium. 

---