Exercise 65. Ammonium Phospho-vanadiotungstate

EXERCISE 65. AMMONIUM PHOSPHO-VANADIOTUNGSTATE, 13(NH4)20-2P206-8V205-34W0s-86H20 

Bring together in a liter flask 1 g. of ammonium phosphate, 15 g. of ammonium tungstate, 3 g. of ammonium vanadate, 20 cc. of ammonium hydroxide, and 700 cc. of water. The ammonium tungstate and vanadate may be prepared from the corresponding anhydrides WO3 and VAX, which are more available. 

Boil the solution for about 6 hr. At first, the solution is colorless but soon changes to yellow and then to red, and to this point the ammonium tungstate dissolves very rapidly. Filter off the slight residue, evaporate to a density of 1.115, and allow to stand overnight. Evaporate the mother liquor for a second crop. The crystals are dark red in color and are octohedra or cubes in form. 

EXERCISE 66. AMMONIUM PHOSPHO-VANADICO TUNGSTATE, 15 (NH ) 2O-2P2O6-6V2O,-44WOs106H2O 

In these and in many other reactions, the ion OH is analogous with NH2.  

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