Zirconium tetrafluoride

Tin reacts completely with fluorine above 190°C to form tin tetrafluoride [7783-62-2] SnF. Titanium reacts appreciably above 150°C at a rate dependent on the size of the particles the conversion to titanium tetrafluoride [7783-63-3] TiF, is complete above 200°C. Fluorine reacts with zirconium metal above 190°C. However, the formation of a coating of zirconium tetrafluoride [7783-64 ] ZrF, prevents complete conversion, the reaction reaching... 

Three binary zirconium fluorides Zrp2, ZrF, and ZrF, are known to exist. The most important compounds industrially are zirconium tetrafluoride, ZrF, and fluorozirconic acid [12021 -95-3], H2ZrF, and its salts (see Zirconiumand zirconium compounds). 

Other applications of zirconium tetrafluoride are in molten salt reactor experiments as a catalyst for the fluorination of chloroacetone to chlorofluoroacetone (17,18) as a catalyst for olefin polymerization (19) as a catalyst for the conversion of a mixture of formaldehyde, acetaldehyde, and ammonia (in the ratio of 1 1 3 3) to pyridine (20) as an inhibitor for the combustion of NH CIO (21) in rechargeable electrochemical cells (22) and in dental applications (23) (see Dentalmaterials). 

Other Reductions. Ductile, pure zirconium has been made by a two-stage sodium reduction of zirconium tetrachloride (68) in which the tetrachloride and sodium are continuously fed into a stirred reactor to form zirconium dichloride [13762-26-0], heating with additional sodium yields zirconium metal. Leaching with water removes the sodium chloride from the zirconium. Bomb reduction of pure zirconium tetrafluoride with calcium also produces pure metal (69). 

Zirconium tetrafluoride [7783-64-4] is used in some fluoride-based glasses. These glasses are the first chemically and mechanically stable bulk glasses to have continuous high transparency from the near uv to the mid-k (0.3—6 -lm) (117—118). Zirconium oxide and tetrachloride have use as catalysts (119), and zirconium sulfate is used in preparing a nickel catalyst for the hydrogenation of vegetable oil. Zirconium 2-ethyIhexanoate [22464-99-9] is used with cobalt driers to replace lead compounds as driers in oil-based and alkyd paints (see Driers and metallic soaps). 

Qua.driva.Ient, Zirconium tetrafluoride is prepared by fluorination of zirconium metal, but this is hampered by the low volatility of the tetrafluoride which coats the surface of the metal. An effective method is the halogen exchange between flowing hydrogen fluoride gas and zirconium tetrachloride at 300°C. Large volumes are produced by the addition of concentrated hydrofluoric acid to a concentrated nitric acid solution of zirconium zirconium tetrafluoride monohydrate [14956-11-3] precipitates (69). The recovered crystals ate dried and treated with hydrogen fluoride gas at 450°C in a fluid-bed reactor. The thermal dissociation of fluorozirconates also yields zirconium tetrafluoride. 

The physical properties of zirconium tetrafluoride ate Hsted in Table 7. 

Zirconium tetrafluoride dissolves in dilute acid without hydrolysis, and can be recovered as the monohydrate [14956-11-3] by crystallization from nitric acid solutions. If the solution is acidified with hydrofluoric acid, ZtF 3H20 [14517-16-9] crystallizes at 10—30 wt % HF HZtF 20 [18129-16-9] crystallizes at 30—35 wt % HF, and at higher HF concentrations H2ZtF -2H20 [12021 -95-3] can be recovered. 

Attempts to prepare zirconium trifluoride, ZrF, by the zirconium reduction of zirconium tetrafluoride were unsuccesshil, but it has been made by heating zirconium hydride to 750°C in a stream of hydrogen and hydrogen fluoride (179). 

Reaction with hydrofluoric acid yields zirconium tetrafluoride ... 

Zirconium fluoride reacts with liquid ammonia, forming the unstable compound, ammino-zirconium tetrafluoride, 2ZrF42NH3. Zirconium tetrachloride forms several ammines. 

Calculate the amount of ammonium fluoride needed to convert the zirconium tetrafluoride to ammonium heptafluozirconate, and weigh a three-fold excess of the substance (why should the excess ammonium fluoride be taken ). Dissolve the ammonium fluoride in a minimum amount of water (see Appendix 1, Table 1), filter the solution, and add it to the zirconium tetrafluoride solution. If no ammonium heptafluozirconate precipitate appears, add 10-20 ml of ethanol. Filter ofi the precipitate with the aid of a Buchner funnel, rinse it several times on the filter with ethanol, and dry it in the air. 

ZIRCONIUM TETRAFLUORIDE see ZQSOOO ZIRCONIUM, dry, coiled wire, finished metal sheets, strip (UN 2858) (DOT) see ZOAOOO... 

The enthalpy of formation of zirconium tetrafluoride was measured by direct combination of the elements in a bomb calorimeter... 

Zirconium Fluoride (Zirconium Tetrafluoride), ZrF j mw 167.22 wh crysts, sp gr 4.43 mp 600°(subl) si sol in cold w decompd by hot w sol in HF. Can be prepd by treating ZrCl with anhyd HF or by thermal decompn of (NH )gZrF, which can be obtd by reacting ZrOg with NH HFg (Refs 1 3). Used as a component of molten salts for nuclear reactors Refs 1) Gmelin-Kraut Syst Number 42(1958), 278 2) Lange(1961), 332 3) Kirk ... 

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 tetrafluoride, Zrp4, is an important component in heavy metal fluoride glasses. It can be prepared by the chemical vapor deposition of zirconium tetrakis (hexafluoroacetylacetonate) (Zr(hfac)4 hfac" 3) [6]. 

Muetterties (376) reports that ethers and sulfones do not react with zirconium tetrafluoride at 50°-160°C, whereas 2 1 adducts of dimethyl sulfoxide, A,A -tetramethylurea, and dimethylformamide were formed upon refluxing a slurry of the tetrafluoride in excess base. The soluble... 

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. 

Larsen and Leddy 333) tried the reduction of zirconium tetrafluoride with zirconium metal, but were unsuccessful. Ehrlich 160) substantiated this observation, but was able to obtain the trifluoride by reacting zirconium hydride with a gaseous mixture of hydrogen fluoride and... 

Dihalides of uncertain purity are prepared by the disproportionation of the trihalides. Alternate routes have also been reported. Swaroop and Flengas (549) prepared ZrCU of 95-99% purity by heating the trichloride and metallic zirconium at 675°C for 30-35 hours in an evacuated quartz tube lined with platinum foil. There is also a reference to the production of liquid dihalides by the reaction of the gaseous tetrahalides with loosely packed zirconium at 700°C for the chloride and 400°C for the bromide and iodide (270). The difluoride has been prepared (357) by the reaction of atomic hydrogen on thin layers of zirconium tetrafluoride at 350°C. New data on hafnium are lacking, although Corbett (542) has concluded that hafnium diiodide does not exist. 

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