OP ARTS AND SCIENCES. 105 



1.0881 gr. lost on ignuion with WO^Xa, 0.1 07G gv. = 9.89 % 

 1.3.560 gi-. " " " 0.1379 gr. = 10.1G% 



1.463G gr. gave 1.1178 gr. WO3 + SbA = '^G.3G % 



1.3425 gr. " with KCy 0.2o2i) gr. Sb = 2.3.12 % SbgO, 



0.909.5 gr. " " 0.1700 gr. Sb = 24.92 % " 



0.8710 gr. " 0.5011 gr. PtClgKa = 11. IG % K2O 



The aualj'ses lead to the formula 



12 WO3 . 4 SboO^ . 6 KoO + 25 aq, 

 which requires : 



Calc'd. Found. 



12 WO3 2784 54.81 55.04 



4 Sb.O^ 1280 25.19 25.12 24.92 



6 K„o' 566 11.14 11. IG 



25 II.,0 450 8.86 8.91 8.64 



5080 100.00 



In calculating the results of the analysis for comparison, I have 

 assumed that, in the ignition with the sodic tungstate to determine the 

 water, antiraonic oxide is reduced to the tetroxide SboO^ ; a correc- 

 tion must therefore be applied to the apparent loss. This amounts to 

 one twentieth of the percentage of antimonic peutoxide, and is of 

 course to be deducted from the totaUIoss. Chemists usually admit the 

 existence of three classes of antimonates, C(jrresponding respectively to 

 metaphosphates, pyropliosphates, and orthophosphates, and formulas to 

 support this view have been somewhat arbitrarily assi<ined to known 

 compounds. If we suppose that the antinionio-tungstate above de- 

 scribed contains metantimonic oxide, we may write the formula as we 

 shall write those of corresponding metaphospho-tungstates, 



12 WO3 . 8 SbOsK . 2 K,0 -}- 25 aq. 



A solution of this salt gives white crystalline precipitates with 

 baric chloride, argentic nitrate, and cupric sul[)hate, and a yellow 

 flocky-crystalline precipitate with mercurous nitrate. 



ANTIMONIO-MOLYBDATES. 



Salts belonging to this group are formed when freshly prepared 

 antimonic hydrate is boiled with an acid molybdate in solution, when 

 antimonic pentachlorid<^ in solulioii in chloi'hydric acid is poured into 

 a solution of an alkaline molybdate in small (piantities at a time, 



