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See detailObservations sur l'hydrolyse du chlorure ferrique
Spring, Walthère ULiege

in Recueil des Travaux Chimiques des Pays-Bas et de la Belgique. 2eme serie (1897), XVI

Spring, W. Rec. trav. chim. Pays-Bas (1897), 16(2), 237-49; SciFinder (Chemical Abstracts Service: Columbus, OH); (accessed July 8, 2010). The decomposition of the ferric ... [more ▼]

Spring, W. Rec. trav. chim. Pays-Bas (1897), 16(2), 237-49; SciFinder (Chemical Abstracts Service: Columbus, OH); (accessed July 8, 2010). The decomposition of the ferric chloride by water already shown of H. Debray (Bulletin of the Chemical Society, Paris 12. 346), after which researcher a very much diluted neutral, nearly colorless iron perchloride solution dissociates with heating up under strong coloring into hydrochloric acid and colloidal ferric oxide. Beside the latter F. W. Krecke (Journal pr. Chemistry 3. 286) found an iron oxychloride compound. After F. Wiedemann (Journal pr. Chemistry, 9. 145) the magnetism of the ferric chloride solutions consists of the sum of the magnetism of the iron in the colloidal oxide and the magnetism of the iron is not changed chloride and therefore no basic salts will give, in which the iron possesses its own atomic magnetism. The studied solutions were middle concentration (30% to 0.06%), however not border lines. Antony and Giglio (Chem.-Newspaper 1895. 325; C. 95. II. 858) the decomposition of the ferric chloride found completed in hydrogen chloride and colloidal hydrate after 24 hours according to colorimetric method with dilutions up to 0.00083%. The latter happens under temporary formation of chlorohydrates, [FeCl2.OH and FeCl(OH)2], which depending upon applied water conditions with hydrogen chloride equilibrium systems form and also cause during the dilution of the irregularities arising in the color of the solution. These changes in the color the line conduction of the iron perchloride solutions follows after Goodwin (Journal of Physik. Chemistry, 21. 1; C. 96. II. 998) a sufficient dilution of the first ionization of the ferric chloride causes, on which the ions (Fe) unite with the ions (OH) first to the colorless, bivalent ions Fe(OH), which gives the colloidal brown ferric hydroxide then with further ions of OH. xFe(OH)... + 2x(OH) = xFe(OH)3. The decomposition of the ferric chloride will exist therefore not in a simple hydrolysis in hydrate and hydrogen chloride, but will be accompanied by ionization features. Solutions concentrated by the author implemented experiments with ferric chloride resulted in the following. Sublimated ferric chloride Fe2Cl6 separates in water without decomposition then only if the relationship of the solvent is extraordinarily small. With the increase of the latter place shift takes place in the ferric chloride, whereby the delivery is prepared of two of the six chlorine atoms. The salt regards now as a composition of Ferrochloride and chlorine Fe2Cl4.Cl2, which dissociates with increase of water completely into the groups of the Fe2Cl4 and Cl2, if these groups can accept the neutral electrical condition. Chlorine in the status nascent reacts then with the water under formation of hydrogen chloride and oxygen, which transfer the group of Fe2Cl4 immediately into the Oxychloride Fe2Cl4O, which accepts the certain following structure: 3Fe2Cl4O = Fe2O3.2Fe2Cl6 and forms with hydrochloric acid and the water an equilibrium system modifying with the temperature. With still further dilution of the solution arrives by the designated phases at the complete decay. In van't Hoff's opinion about the nature of the solutions proven that the expansion of a salt draws the same consequences by its solvent, like those by increase of the temperature. Reaction of the potassium ferricyanide. Potassium ferricyanide does not give a low-brown color with ferric salt solutions of middle concentration, a clear reaction with a very much concentrated solution of ferric chloride (230%), with a 126% solution against it immediately a precipitation of citizen of Berlin blue and development of chlorine, from which it must be closed that the ferric chloride splits in the solution into Ferrochloride and chlorine: Fe2Cl6 = Fe2Cl4 + Cl2. Similarly behave after author ferric bromide, ferric iodide and ferric nitrate, only takes place slower at the latter the formation precipitation of citizen of Berlin-blue, therefore the dissociation: Fe2(NO3)4 + N2O5 + O seems to take place with difficulty; more rapidly the latter is caused with addition by some barium carbonate. Despite this behavior one may not really regard a solution of ferric chloride consisting of Fe2Cl4 and Cl2, as soon as chlorine leaves the compound, with the Fe2Cl4 and Cl2 an electrical charge is caused, whereby the Ferrochloride as cation and chlorine function as anion. Between these ions results an electrostatic attraction, which opposes its complete separation. Chlorine reacted with the water under formation from HCl, what latter by an air flow can be removed, while the oxygen remains connected with the group of Fe2Cl4 : Fe2Cl6 + H2O = Fe2Cl4O + 2HCl. About the reaction of the iron with ferric chloride. A metal plate from iron does not react nearly with a saturated ferric chloride solution. The iron separates into less concentrated solutions, all faster, the more easily these solutions with potassium ferricyanide give citizen of Berlin-blue. It is not the formation of the Ferrochloride, a consequence of the dissolution of the iron, but is from the latter cause, as due to the dissociation (see above) formed hydrochloric acid dissolves the iron under development of hydrogen. If with these location of the ferric chloride, the FeCl2 cation and Cl2 anion and between these ions make an electrostatic attraction valid (see above), then must have a difference of potential be stated and an electric current to be able to collected, whose intensity will depend on the dissociation of the ferric chloride. On the other hand, one will cause the delivery of the ions with the current conclusion, brings and/or the dispersion of FeCl2 and Cl2 without difficulty to conditions - an opinion, which was confirmed by the experiment. A small platinum cap flat at the reason is fastened on by means of metal catch of the ends of a galvanometer, given into the same a confirmed FeCl3-solution (laminate 5-6 mm) and brought a small iron disk (2 cm diameters)on the surface of the liquid which is connected with the other end of the galvanometer. In instants of the contact, the needle turn out into violent oscillations and places with the division 54°. After 4 hours, 4 cg had more separated iron than in a simultaneous experiment which the flow was not closed. The latter went from the iron to platinum, so that this cathode and the iron were anode. With the use of more diluted solutions of FeCl3 increases the intensity of the flow up to a solution of 40%, on which it decreases with the further dilution regularly, thus it goes through a maximum. Also the ease give with solutions of ferric chloride citizen of Berlin-blue under delivery of chlorine, walks by a maximum. In the end it is noticed that the investigations of the author, also contribute to the answer of the question of the molecular formula of the ferric chloride, which after the density of the formula Fe2Cl6, according to the b.p.-method in alcohol or ether solution however comes the formula FeCl3. It is still determined whether the place mixture of chlorine in the ferric chloride has solution not also in alcoholic or ethers. Reprinted with the permission of the American Chemical Society. Copyright © 2010. American Chemical Society (ACS). All Rights Reserved. [less ▲]

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