96 PROCEEDINGS OF THE AMERICAN ACADEMY 



argentic nitrate, which becomes darker on boiling, and finally deep 

 chocolate-brown. This reaction resembles that of the phospho-hypo- 

 phospho-tungstates. The solution gives a very pale yellow indistinctly 

 crystalline precipitate with mercurous nitrate, which is not reduced by 

 boiling, and a white flocky precipitate with baric chloride. The salt 

 dissolves with much difficulty in ammonia-water, but easily in solutions 

 of alkaline carbonates. Chlorhydric acid gives a white precipitate in 

 these solutions, readily soluble in ammonia. In this salt, 



f 1.5373 gr. lost on ignition 0.0578 gr. = 3.76% 

 ( 1.5373 gr. gave 1.3702 gr. mixed oxides = 89.13% WO. and P2O5 

 1.7603 gr. " 0.1138 gr. PgO^Mga = 4.13% P0O5 

 2.7325 gr. « 0.0836 gr. " = 1.96% « 



In determining PO3H3 the solution in COoNag was oxidized by 

 bromine. 



The analyses correspond with the formula 



24 WO3 . 2 PO3H3 . P0O5 . 5 KoO + 13 aq, 



6570 100.00 



When a solution of phosphorous and chlorhydric acids is mixed 

 with one of the 24 : 1 phospho-tungstate of sodium, 



24 WO3 . P2O, . 2 Na^O -f 27 aq, 



no precipitate is formed, but after a time relatively large colorless 

 measurable crystals of the phospho-tungstate are deposited. 



PHOSPHOROSO-PHOSPnO-MOLYBDATES. 



72:3:2:9 Ammonic Phosphor oso-pJiospho-molyhdate. — When the 

 solution of phosphorous and chlorhydric acids obtained by treating 

 phosphorous terchloride with cold water is mixed with a solution of 

 10 : 2 ammonic phospho-molybdate, a greenish-yellow crystalline pre- 



