of Molybdenum and some of its Compounds. 539 



apparatus so that only dry chlorine gas could pass over the 

 oxide. When the apparatus had become filled with chlorine 

 gas at the ordinary temperature at which no action is exerted 

 upon the oxide, we applied a very gentle heat to the bulb 

 containing the oxide : chlorine was absorbed with great avi- 

 dity ; biacichloride of molybdenum was formed, which was 

 driven by a very gentle heat into the other bulb. When in 

 this manner the greater portion of the oxide had been con- 

 verted into the volatile chloride, the bulb was allowed to cool, 

 and a current of dry air then passed through the apparatus for 

 some time, to expel all chlorine gas, and the bulb containing 

 the biacichloride melted off. This portion of the tube and its 

 contents was weighed, the one extremity of the fused tube cut 

 off, the contents dissolved in water, and after the tube had been 

 well washed with water, dried and weighed, the loss furnished 

 us with the amount of biacichloride taken for analysis. This 

 chloride is readily soluble in water, but gave a faintly opalescent 

 solution. When the solution had been very much diluted 

 with water, we added a small quantity of nitric acid and then 

 some nitrate of silver. At first pure chloride of silver fell, 

 readily recognisable from its colour and external appear- 

 ances; but on adding some more of the silver solution, the 

 precipitate became very bulky and assumed a yellowish colour. 

 On heating the solution, to cause the chloride of silver to sub- 

 side and to dissolve the molybdate of silver which had been 

 precipitated with it in the nitric acid, the liquid became more 

 and more turbid, the precipitate increased, and the liquid, 

 after twenty-four hours standing, still remained turbid. We 

 now filtered, but with the precaution of pouring only the 

 liquid on the filter; and after the precipitate had been washed 

 several times in the beaker with hot water containing nitric 

 acid, the whole was dissolved in dilute ammonia, and then 

 nitric acid again added. These operations of dissolving, pre- 

 cipitating, and reprecipitating were repeated several times, for 

 this was the only way of separating the whole of the molyb- 

 date of silver; finally, the chloride of silver was poured upon 

 the filter and determined in the usual manner. 



3*0881 grms. of biacichloride of molybdenum furnished 

 4'3245 chloride of silver •= 1*069 chlorine. 



If we compare the per-centage composition according to 

 analysis and theory, we have — 



a. Calc. *>. Calc Found. 



2 at. Molybdic acid 1 777*932 48095 1751-658 47895 



1 at. Molybdenum 588966 15*932 575*829 15*744 



Cat. Chlorine 1329*840 35-973 1329*840 36 661 34*622 



3686*738 100 000 3657327 100*000 

 2 N2 



