100 PROCEEDINGS OP THE AMERICAN ACADEMY 



88.26 



12070 100.00 



12:2:2:6 Sodio-potassic Arsenoso-phospho-tungstate. — "When 

 sodic phospho-tungstate, 



24 WO3 . P0O5 . 2 Na.O + 27 aq, 



in solution, is boiled with arsenous oxide in excess, this last dissolves 

 freely to a colorless or nearly colorless liquid. On adding ammonic 

 chloride no precipitate is formed, but after acidulating with chlorhydric 

 acid a white crystalline precipitate is thrown down. On standing, the 

 supernatant liquid deposits very distinct pale yellow tabular crystals. 

 When potassic bromide is added to the sodic solution, a yellow oil 

 separates after a time, which dries to a pale yellow gummy transparent 

 mass. Of this salt, 



0.9284 gr. lost over a radiator 0.0595 gr. = 6.41 c^^ 

 0.9492 gr, gave 0.0822 gr. As.Og with iodine = 8.65 f>^ 

 1.2191 gr. " 0.1061 gr. " " = 8.70^ 



0.8961 gr. " 0.0944 gr. PgO.Mgo = 6.74% P2O5 



5 0.8916 gr. " 0.6458 gr. P^O^ + WO, = 72.43% 

 (0.8916 gr. " 0.5064 gr. PtCl.Ka = 11.03^^ K2O 



The formula which best represents the analyses is 



12 WO3 . 2 AS2O3 . 2 PgOs . 5 K2O . NasO + 15 aq, 



4268 100.00 



