Iron ammonium alum sulphate

Ferric ammonium alum or Iron ammonium alum, (NH4)2S04. Fe2(S04)3.24H20, has been obtained by electrolysing a solution of ferrous sulphate and ammonium sulphate.3 The cathode consists of platinum wire immersed m acidified ferrous sulphate solution contained in a porous pot. An acidulated solution of ferrous and ammonium sulphates surrounds the pot, and is contained m a platinum dish which serves as anode. A current of 0-04 ampere is passed through the cell, and after several hours crystals of the alum are deposited round the anode. 

Ferrous Ammonium Sulphate, FeS04-(NH4)2S04-6H20, and Ferric Ammonium Alum, Fe2(S04).r (NtL SCh H O, from Iron... 

A mmonio-ferric sulohste 4738 Fej (NK4) 3(804)4 2 3H20 Ammonlo-farrlc alum sulphate of iron end ammonium,... 

Dissolve 100 g. of iron alum (ferric ammonium sulphate) in 300 ml. of water at 65°, Pour the solution, with stirring, into a solution of 25 g. of hydroquinone in 100 ml, of water contained in a 600 ml. beaker. The quinhydrone is precipitated in fine needles. Cool the mixture in ice, filter with suction, and wash three or four times with cold water. Dry in the air between filter paper. The yield of quinhydrone, m.p, 172°, is 15 g. It contains a trace of iron, but this has no influence upon the e.m.f, of the quinhydrone electrode provided that the washing of the crude material has been thorough. The quinhydrone should be stored in a tightly-Btoppered bottle. 

F-test 140, (T) 841 Faraday constant 60, 504 Faraday s laws 503, 504 Fast sulphon black F 319 Fats D. of saponification value, (ti) 308 Ferric alum indicator see Ammonium iron(III) sulphate... 

Both iron and cobalt, when trivalent, yield stable double sulphates with ammonium and the alkali metals, containing twenty-four molecules of water. These arc known as alums, and to them the general formula MaS04.Ba(S04).).2I.Ha0 may he ascribed. They usually crystallise in well-defined octahcdra. Nickel, on the contrary, does not yield salts of this type, since nickelie sulphate cannot exist. 

Aqueous solutions of the alum rapidly become turbid when dilute, although concentrated solutions remain clear for several months. Addition of ammonium sulphate increases the hydrolysis, whilst sulphuric acid exerts a marked retarding influence. The precipitate consists of a basic sulphate of iron, 2Fe203.S03, and the hydrolysis is believed 4 to follow the course indicated by the equations —... 

AMMONIUM IRON SULPHATE (Alum) (NH4)2Fe2(S04)4.24H20. 

The octahedral, cubic crystals are violet to black in colour, and appear ruby-red in thin layers and J. H. Kastle found that the intensity of the colour is very much reduced at liquid air temp. F. Klocke, C. F. Rammelsberg, C. von Hauer, and J. W. Retgers showed that the crystals are isomorphous with other alums, for they show similar corrosion figures. E. Dittler obtained overgrowth with potassium aluminium sulphate. T. V. Barker found a close connection between parallel overgrowths in chrome-alum, potash-alum, and ammonia-alum and the mol. vols which are respectively 542-2, 541-6, and 552-2. C. von Hauer found that with the introduction of a crystal of iron-alum in a sat. soln. of chrome-alum nearly all the latter separates out while L. de Boisbaudran found that a sat. soln. of basic ammonium aluminium alum does not affect the octahedral faces of the... 

Mitscherlich also measured the angles of the crystals of double sulphates of potassium and ammonium with magnesium, ferrous iron, manganese, zinc, copper, cobalt and nickel. This established the isomorphism of potassium and ammonium sulphates. He found that the double potassium sulphates had one proportion of water more than the double ammonium sulphates, and also obtained a salt crystallising in beautiful and large octahedra with exactly the same composition as alum but containing ferric oxide instead of alumina (ferric alum). He says he hoped to show that a study of crystallisations would give the compositions of bodies as certainly and definitely as chemical analysis . A letter from Humboldt to Mitscherlich said this beautiful work had exposed the incorrectness of Haiiy s view. ... 

Indicator solution. Dissolve 40 g of ammonium iron(III) sulphate dodecahydrate (ferric alum) in a mixture of 20 cm of nitric acid water (3 5 v.v) and 80 cm of water. Heat to boiling and dilute with 3 volumes of water. 

To about 0-4 g of mercury add 20 ml of 1 1 nitric acid, boil until the solution is colourless, cool and dilute. Add potassium permanganate solution until no further decolorisation occurs, removing any excess with a trace of ferrous sulphate and titrate with 0-lN ammonium thiocyanate, at a temperature not exceeding 20°, using iron alum as indicator. 1 ml O IN = 0 01003 g Hg. 

A number of dilute chemical solutions attack tin metal slowly, with consequent corrosion. Among these are aluminium chloride, aluminium potassium alum, ammonium sulphate, hydrochloric acid, hydrobromic acid, hydriodic acid, fluorine, chlorine, bromine, iodine, iron(III) chloride, potassium carbonate, potassium hydroxide, silver nitrate, zinc chloride, glycerol and maleic acid. ... 

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