Ferric hydrate

The temperature at which the reduction by the hydrogen takes place varies with the different oxides and also with the same oxide, depending on its physical condition. " Crystalline haematite, as the naturaJ ferric oxide is called, requires to be at a red heat (about 500° C.) before reduction begins to tadce place, while if iron is precipitated from one of its salts (as ferric hydrate by... 

Starkey, R.L., 1945. Precipitation of ferric hydrate by iron bacteria. Science, 102 532— 533. 

Hydrates.—PEiutors.—When a solution of a ferrous salt is decomposed by on alkaline hydrate, a greenish-white hydrate, FeH,0, is deposited which rapidly absorbs O from the air, with formation of ferric hydrate. 

If the normal hydrate bo dried in vacuo it is converted into (Fe, ).jH,0, and this, when boiled for some hours with H,0, is converted into the colloid, or modified hydrate (Fe,)H,0, ( ), which brick-red in color almost insoluble in HNO, and HCl ves no Prussian blue reaction, and forms a turbid solution with acetic acid. If recently precipitated ferric hydrate be dissolved in solution of ferric chloride or acetate, and subjected to dialysis, almost all the acid passes out, leaving in the dialyzer a dark-red solution, which probably contains this colloid hydrate, and which is instantly coagulated by a trace of H,SO, by alkalies, many salts, and by heat dialyzed iron). 

Fkbrio Acetates.—The iorma/ so. /, (Fe,)(C,H,0,), is obtained by adding slight excess of ferric sulphate to loatl acetate, and decanting aftei twenty-four hours. It is dark red, unciystallizable, very soluble in alcohol and in H O. I its solution be heated it darkens suddenly, gives ofl acetic acid, and contains a basic acetate when boiled it loses adl its acetic acid and deposits ferric hydrate when heated in closed vessels to 100 (212 F.), and treated with a trace of mineral acid, it deposits the modified ferric hydrate. 

Ferric Tartrate—3F e,(C,H O,), -f 3 —655.8 + 64.—A dirty yellow, amorphous mass, obtained by dissolving recently precipitated ferric hydrate in tartaric acid solution, and evaporating below 50 (122 F.). 

Aq—489.8 + 108—is in garnet-colored scales, obtained by dissolving ferric hydrate in solution of citric acid and evaporating the solution at about 60° (140° F.). It loses 3 Aq at 120 (248 F.), and the remainder at 150° (302 F.). if a small quantity of ammonia be added before the evaporation, the product consists of the modifed citrate = ferri et ammonii citras (T,. ), which only reacts with pota um ferrocyanide after addition of... 

If, in place of bringing two solutions in contact with each other, they be separated by a solid or semi-solid, moist, colloid layer, diffusion takes place in the same way through the interposed layer. Advantage is taken of this fact to separate crystalloids from colloids by the process of dialysis. The mixed solutions of ciystalloid and colloid are brought into the inner vessel of a dialyser. Fig. 13, whose bottom consists of a layer of moist parchment paper, while the outer vessel is filled with pure water. "Water passes into the inner vessel, and the crystalloid passes into the water in the outer vessel. By frequently changing the water in the outer vessel, solutions of the albuminoids or of ferric hydrate, etc., almost entirely free from crystalloids, may be obtained. 

Any iron that the marble may contain in the state of carbonate passes into solution as ferrous chloride, and is converted into ferric chloride and ferric hydrate by the calcium hypochlorite. 

Synonyms.—Moist Ferric Hydrate Ferri Peroxidum Hydratum Moist Hydrated Peroxide of Iron. 

Synonyms Cl 77492 Ferric hydrate Ferric hydroxide Ferric hydroxide oxide Ferric oxide hydrated... 

Ginsberg, H., W. Huttig, and H. Stiehl, 1961. The precipitation of aluminum hydroxides from alumin-ate and aluminum salt solution. The H2O— AliOa system. Z. Anorg. Allgem. Chem. 309 233. Glemser, O., 1959. Binding of water in ferric hydrate. Nature 183 1476. 

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