Ferric fluoride

In place of sodium silicofluoride, sodium ferric fluoride (Na3FeF6) can also be used for fluorination ... 

Sodium ferric fluoride is obtained as a byproduct in the solution processing of Na2BeF6 leach liquor. It is used for substituting for sodium silicofluoride (to an extent of up to 60%) in the ore fusion reaction. 

Ives and Hirth (6) report similar data for etch pits in LiF, in which the rate of pit widening drops to 0 at 0.22CQ and 32°C in dilute ferric fluoride solution, where the 2.5 ppm FeJ acts as a dissolution poison. They argue that, when no poison is present, the rate should decrease linearly with increasing C/CQ, until the rate equals 0 at C CQ. In the presence of a poison adsorbed to a kink, however, dissociation of a molecule should be slowed, reducing the local equilibrium concentration to a value of C < CQ. If poison molecules completely cover the kink sites, the rate of pit widening could reach 0 at C rather than CQ. The contribution of poisons to... 

Iron Fluoride. See Ferric Fluoride in this Section... 

In Figure 7, the MCD spectra of high- as well as low-spin ferric iron chlorin derivatives are displayed (38, 39). The high-spin ferric-fluoride adducts of methylchlorin-reconstituted myoglobin and horseradish peroxidase are compared in Figure 7A. For the ferric low-spin case, the... 

Figure 7. MCD spectra of the (A) high-spin ferric-fluoride adducts of...

Ammonium ferrifluoride, (NH4)3FeF69 is prepared by nearly neutralising a solution of ferric fluoride in hydrofluoric acid with ammonia, and evaporating.3... 

Barium ferrifluoride, Ba3(FeF6)2, is obtained as a precipitate when barium chloride is added to an aqueous solution of ferric fluoride.4... 

Sodium fluoride and ferric fluoride yield a eutectic mixture, melting at 892° C. and corresponding m composition to the formula 65 NaF. 35FeFs.8... 

Thallous ferrifluoride, 8TlF.2FeF3, is obtained as pink crystals on evaporating a solution of thallous fluoride and excess of ferric fluoride.9... 

FERRIC FLUORIDE (7783-50-8) FjFe Noncombustible solid. Forms acid solution in water. Contact with strong oxidizers may cause fire and explosions. Aqueous solution is incompatible with sulfuric acid, organic anhydrides, alkalis, bases, amines, amides inorganic hydroxides ammonia, alkylene oxides, amides, epichlorohydrin, isocyanates, vinyl acetate. 

Which should have the higher boiling point, ferric chloride or ferric fluoride ... 

This hydroxide precipitate can be filtered and passed to later purification stages. The filtrate contains a fairly dilute solution of sodium fluoride which, if completely recovered, could in theory make the process completely self-sustaining in fluorine compounds. A method proposed by Kawecki precipitates sodium ferric fluoride, by the addition of ferric sulphate to the solution, after bringing to a pH of 4 by the addition of sulphuric acid, i.e. 

The sodium ferric fluoride can then be used directly to replace sodium silicofluoride in the main breakdown reaction ... 

In practice higher fluorine and beryllium efficiencies are obtained if a small amount of sodium carbonate is added to the sodium ferric fluoride reaction, as with the silicofluoride reaction, although in the former case it is not strictly required according to the generally accepted equation. It has been... 

The beryl is ground, wet or dry, to about 200 mesh in a ball mill, and then mixed with the sodium ferric fluoride and sodium carbonate in a wet condition. Briquettes are fabricated from the paste, dried and sintered, e.g. by passing continuously through a gas-heated tunnel kiln with a residence time of several hours at 750 C. A rotary kiln would probably not be very satisfactory since the briquettes are somewhat plastic and would tend to adhere to the lining. ... 

A pseudooctahedral [Fe(N3)4(DMSO)2]" ion is produced with excess of azide ions i, but the last two dimethyl sulphoxide positions cannot be replaced by azide ions. Thus autocomplex formation is predicted for ferric azide, although the latter has not been described yet. Likewise no ferric fluoride is formed when fluoride ions are added to the solution of iron(III) perchlorate. Again autocomplex formation takes place si ... 

Table 4.2. Variation of the saturated hyperfine field with magnetic dimensionality for ferric fluorides...

Fig. 18. Structures of ferric fluoride and ferricyanide, illustrating hexacovalent bonding. Elach dash represents a pair of electrons.

A filter paper impregnated with ferric fluoride forms red ferric thiocyanate with thiocyanate and calcium ions. The filter paper is moistened with 0,1 N ferric chloride solution, dried, dipped into a 0.6 iV solution of NaF or KF and again dried. To this paper is added 1 drop of 0.1 N potassium thiocyanate and 1 drop of the test solution. A red spot is formed in the presence of calcium. Idn. Limit 0.04 y Ca) ... 

Procedure. A drop of the add test solution is placed in a porcelain micro crucible coated with paraffine. The yellow solution is decolorized by adding a few crystals of potassium fluoride. Then a drop of the reagent solution is added. In the presence of iron salts, a red or pink coloration appears. In the absence of ferrous salts, the solution remains colorless, or a precipitate (complex potassium ferric fluoride) may separate. 

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