ferrocyanide's Usage Examples:

Of the principal workers in this field we may notice Friedrich Hoffmann, Andreas Sigismund Marggraf (who detected iron by its reaction with potassium ferrocyanide, and potassium and sodium by their flame colorations), and especially Carl Scheele and Torbern Olof Bergman.

They give a characteristic pale red precipitate with sodium pyrophosphate, soluble in an excess of the precipitant; they also form precipitates on the addition of platinic chloride and potassium ferrocyanide.

It may also be prepared by heating a mixture of carbon, oxide of iron and magnesite to bright redness; and by heating a mixture of magnesium ferrocyanide and sodium carbonate, the double cyanide formed being then decomposed by heating it with metallic zinc.

Ammonia gives a characteristic blue coloration when added to a solution of a copper salt; potassium ferrocyanide gives a brown precipitate, and, if the solution be very dilute, a brown colour is produced.

The ferrocyanide solution is standardized by dissolving i gramme of pure zinc in 6 cc.

Experiments with membranes of copper ferrocyanide have verified this result for solutions of cane-sugar of moderate dilutions.

Ferrous salts also give a bluish white precipitate with ferrocyanide, which on exposure turns to a dark blue; ferric salts are characterized by the intense purple coloration with a thiocyanate.

Potassium ferricyanide, K 3 Fe(NC)s, red prussiate of potash, is obtained by oxidizing potassium ferrocyanide with chlorine, bromine, 'c.

Rossler and Hasslacher prepare the double potassium sodium cyanide by fusing potassium ferrocyanide with sodium, the product of fusion being extracted with water and the solution evaporated: K 4 Fe(NC) 6 +2Na Fe+ 4KNC 2NaNC.

It was found, for instance, that a film of insoluble copper ferrocyanide, deposited in the walls of a porous vessel by the inward diffusion and meeting of solutions of copper sulphate and potassium ferrocyanide, would allow water to pass, but retained sugar dissolved in that liquid.

The zinc sulphate is added in order to remove the ferrocyanide formed as an insoluble zinc salt: 2K 3 Fe(NC)6+2KI2K 4 Fe(NC) 6 -0 2.

Potassium cyanide may be obtained by fusing potassium ferrocyanide either alone - K4Fe(NC)64KNC+ FeC2+N2 - or with potassium carbonate [V.

Synonyms:

salt, potassium ferrocyanide, yellow prussiate of potash,

Antonyms:

dull,