Ferric oxide hydrates

Composi- Ferric oxide hydrate bonded to Complex of ferric Complex of polynuclear... 

Tetrapyridino ferrous chloride (synthesis 64) is dissolved in distilled water in the ratio of 20 g. per liter and placed in a flask of suitable size. Clean air or oxygen is then allowed to bubble through the solution, rapidly for about 15 minutes and then slowly for an additional 30 minutes or longer. This converts the tetrapyridino ferrous chloride complex into the orange-yellow gamma ferric oxide hydrate, 7Fe203-H20.1,2 3,4 5 The yield is substantially quantitative. 

Baudisch, O. and Albrecht, W. H. (1932) Gamma ferric oxide hydrate. I Amer. Chem. Soc. 54 943-947. 

Asami, T., Behavior of free iron oxide in paddy soils. Part 5. On the reduction of synthesized ferric oxide hydrates and ferric oxides in paddy soils, J. Sci. Soil Manure Jpn, 41, 56, 1970. 

Composition Ferric oxide hydrate bonded to sucrose chelates with gluconate in a molar rate of 2 iron molecules to 1 gluconate molecule Complex of ferric hydroxide and dextran Complex of polynuclear iron hydroxide in sucrose... 

Ferric oxide hydrated. See Iron (III) oxide hydrated... 

Calcium bromide Citric acid Ferric oxide Hydrated lime Manganic oxide Natural fatty acids Potassium bromide Potassium chloride Potassium sulphate Phosphate esters Silicates (inorganic)... 

The Penniman-Zoph process involves the preparation of seeds or nucleating particles by the alkaU precipitation of ferrous sulfate. The reaction is carried out at alow temperature using an excess of ferrous ions. The hydroxide is then oxidized to the seeds of hydrated ferric oxide ... 

Iron Browns. Iron browns are often prepared by blending red, yellow, and black synthetic iron oxides to the desired shade. The most effective mixing can be achieved by blending iron oxide pastes, rather than dry powders. After mixing, the paste has to be dried at temperatures around 100°C, as higher temperatures might result in the decomposition of the temperature-sensitive iron yellows and blacks. Iron browns can also be prepared directiy by heating hydrated ferric oxides in the presence of phosphoric acid, or alkaU phosphates, under atmospheric or increased pressure. The products of precipitation processes, ie, the yellows, blacks, and browns, can also be calcined to reds and browns. 

The yellow oxides are prepared by precipitating hydrated ferric oxide from a ferrous salt usiag an alkaU, followed by oxidation. The shades obtained range from light lemon yellow to orange, depending on the conditions used for the precipitation and oxidation. Yellow oxides contain about 85% Fe202 and 15% water of hydration. 

Brown combinations usually contain iron with chromium, zinc, titanium, or aluminum. There are a few without iron that contain chromium, antimony, tin, zinc, manganese, or aluminum. They range from tight tans to dark chocolate. The shades ate not as red as ferric oxide, but the browns are far superior to hydrated iron oxide in brightness and thermal stability. 

A hydrated silica-alumina compound, associated with ferric oxide. Used as a filter medium and as a catalyst and catalyst carrier and in cosmetics and insecticides. 

Supporting the hydrated ferric oxide chips is a combination of a perforated, heavy metal support plate and a coarse support packing material. This material may consist of scrap pipe thread protectors and 2-3-in. sections of small diameter pipe. This provides support for the bed, while offering some protection against detrimental pressure surges. 

The product, ferrous hydroxide, is commonly further oxidised to magnetite (Fej04) or a hydrated ferric oxide (FeOOH), i.e. rust. 

In rusting, the initial corrosion product of iron is ferrous hydroxide. Reacting with oxygen and water, it forms higher oxides, mainly hydrated ferric oxide and magnetite. Rust formed in industrial or marine environments contains corrosion-promoting salts and is particularly dangerous. Rust is not considered a satisfactory base over which to paint and it too must be removed. 

For steel, passivation is achieved by the surface formation of a tough, adherent mixture of oxides. The passive film is primarily gamma-magnetite (y-Fe203) but also contains gamma-hydrated ferric oxide (y-FeOOH). The film thickness is perhaps 15 A to 30 A (angstrom units). 

In the goethite process, the precipitation of iron from solution occurs in the form of hydrated ferric oxide, FeOOH. The commercial development of the process was due to Societe de La Vielle Montagne. The process basically involves the reduction of iron to the ferrous state, and this is followed by oxidation by air at a temperature of around 90 °C and at a pH controlled at around 3.0. The reaction can chemically be shown as ... 

The core of the iron storage protein ferritin consists of a hydrated ferric oxide-phosphate complex. Various models have been proposed which feature Fe111 06 oct., Fe111 O4 tet. or Fe111 O4 tet. Fe111 06 oct. complexing the first listed is preferred by Gray (99) on the basis of the electronic absorption spectrum. The protein very closely related to ferritin which occurs in the mold Phycomyces blakesleeanus contains... 

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