Aluminium ferrocyanide

Aluminium ferrocyanide, Al4[Fe(CN)6]3.17H20, is formed when solutions of alum and potassium ferrocyanide are mixed in the cold,5 the alum being (presumably) in excess6 otherwise the double aluminium ammonium salt is produced. 

Potassium aluminium ferrocyanide, KAlFe(CN)6.4H20.—Considerable difficulty attends the preparation of this salt,8 which forms a jelly on mixing equivalent solutions of aluminium chloride and potassium ferrocyanide. By centrifugating at 3000 revolutions per minute it may be isolated as a precipitate, washed with acetone and ether, and dried in vacuo. The salt is dark green, and transparent when in bulk, but when powdered is light bluish green. At 100° C. it becomes anhydrous and assumes a deep blue colour. 

Sodium aluminium phosphate, acidic Sodium aluminium silicate Sodium benzoate Sodium calcium polyphosphate Sodium carbonate Sodium ethyl p-hydroxybenzoate Sodium ferrocyanide Sodium gluconate... 

There are several salts that behave in this way at atmospheric temperatures, the more important being ammonium acetate potassium bromate, carbonate, cyanide, ferricyanide, ferrocyanide, iodate, and permanganate disodium hydrogen phosphate and sodium borate and carbonate.4 In the case of potassium chlorate the points L and S appear to be practically coincident, whilst for the majority of salts the point S lies somewhere to the left of L, namely at S —that is to say, saturation occurs before the limiting concentration is reached. Generally speaking, at the ordinary temperature, concentrated solutions of salts are less corrosive than distilled water—that is, the point S lies below the level of A, exceptions being 5 ammonium sulphate, aluminium... 

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