Iron -fluoride FeF

Iron chloride (FeClg) Iron chloride (FeClg) Iron chloride (FeClg) Iron chloride ((FeClg)g) Iron chloride ((FeClg)g) Iron fluoride (FeF)... 

Anhydrous FeF is prepared by the action of Hquid or gaseous hydrogen fluoride on anhydrous FeCl (see Iron compounds). FeF is insoluble in alcohol, ether, and ben2ene, and sparingly soluble in anhydrous HF and water. The pH of a saturated solution in water varies between 3.5 and 4.0. Low pH indicates the presence of residual amounts of HF. The light gray color of the material is attributed to iron oxide or free iron impurities in the product. 

Thermal dissociation produces ammonium fluoride and ammonia at elevated temperatures products contain ammonia and hydrogen fluoride. It forms a colorless double salt, ammonium iron fluoride SNEUF FeFs, with iron, a reaction of commercial apphcation for removing stains from fabric. It reacts with many metal oxides at elevated temperatures forming double fluorides ... 

Electrochemical activity of iron-III fluoride (FeFs) was first reported by Arai et al. [125]. The compound has theoretical capacity of approximately 200 mAh/g in the 4.5-2.5 V region and 400 mAh/g in the 2.5-1.5 V region. Li et al. [12] and Amatucci and co-workers [13, 14, 126] have since proposed reaction mechanisms for the higher and lower voltage windows ... 

Fe +/Fe°) can be achieved (4.5 to 1.5 V) with a specific capacity in the first cycle of 770 mAh/g FeFs, which is close to the theoretical value and in accordance with the full conversion of iron fluoride. 

Hydrated iron(III) fluoride [15469-38-2] is easily prepared from yeHow Fe202 and hydrofluoric acid. Dehydration of FeF 3H20 produces... 

Iron(III) fluoride ttihydrate [15469-38-2] FeF3-3H2 0, crystallizes from 40% HF solution ia two possible crystalline forms. At low temperature the a-form, which is isostmctural with a-AlF 3H2O, is favored. High temperatures favor P-FeF 3H2O, the stmcture of which consists of fluoride-bridged octahedra with one water of hydration per unit cell. 

Iron hahdes react with haHde salts to afford anionic haHde complexes. Because kon(III) is a hard acid, the complexes that it forms are most stable with F and decrease ki both coordination number and stabiHty with heavier haHdes. No stable F complexes are known. [FeF (H20)] is the predominant kon fluoride species ki aqueous solution. The [FeF ] ion can be prepared ki fused salts. Whereas six-coordinate [FeCy is known, four-coordinate complexes are favored for chloride. Salts of tetrahedral [FeCfy] can be isolated if large cations such as tetraphenfyarsonium or tetra alkylammonium are used. [FeBrJ is known but is thermally unstable and disproportionates to kon(II) and bromine. Complex anions of kon(II) hahdes are less common. [FeCfy] has been obtained from FeCfy by reaction with alkaH metal chlorides ki the melt or with tetraethyl ammonium chloride ki deoxygenated ethanol. 

Selenites and selenates are quantitatively reduced to elementary selenium when their acid solutions are warmed with ferrous sulfate. In contrast, tellurite and tellurate solutions remain unaltered because the redox potential of iron is not sufhcient to accomplish the reaction Fe i + Teiv(vi) Fe -f Te°. However, the reducing power of Fe+ ions can be raised considerably if the Fe+ ions are removed as soon as they are produced. Phosphoric acid is excellent for this purpose it immediately converts the Fe+ ions into [Fe(P04)2] " ions. Fluorides act analogously through the formation of [FeF,]- ions. Consequently, when tellurites or tellurates are warmed with a ferrous sulfate-phosphoric acid mixture there is complete reduction to free tellurium. 

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