340 W. A. Turner — Vanadium Determined by Ciqiferron. 



In this way the following resnlts were obtained : 



Table I. 



Gms. of NH 4 V0 3 Gms. of V 2 5 Gins, of V 2 6 per 

 Exp. solution taken found 25 gnis. of sohitiou 



1 



25'9374 



0-1714 



0-1652 



9 



25-9846 



0-1747 



0-1681 



3 



25'6772 



0-1699 



0-1654 



4 



25-9426 



0-1727 



0-1664 



These results not being wholly satisfactory in establishing 

 the vanadium content of- the solution, it was decided to try the 

 apparently simple method of evaporating weighed portions of 

 the solution, igniting the residues and weighing the amounts of 

 vanadium pentoxide obtained. In this process also the presence 

 of hydrochloric acid is an inconvenience. The results obtained 

 were too low. It was noted that in the ignition some volatile 

 product was formed which was deposited on the cover and the 

 outer edges of the crucible. It is probable that some of the 

 very volatile oxychloride, VOCl 3 , is formed. An attempt was 

 made to prevent this by evaporating the solution with sul- 

 phuric acid and thus remove hydrochloric acid, but under these 

 conditions high results were obtained evidentl} 7 due to the 

 formation of a not readily decomposable vanadium sulphate. 

 Simple evaporation and ignition of the ammonium vanadate 

 solution was finally again resorted to and by a careful regula- 

 tion of the heat (the temperature being very gradually increased 

 from the lowest possible flame of a Bunsen burner to the high 

 heat of the Meker burner) the following quite concordant 

 results were obtained : 





Table II. 







Gms. NH4VO3 



Gms. of V a O B 



Gms. of V 2 5 per 



Exp. 



solution taken 



found 



25 gms. of solution 



5 



25-4215 



0-1679 



0-1651 



6 



25-4215 



0-1680 



0-1652 



7 



25-4215 



0-1683 



0-1655 



8 



25-4215 



0-1690 



0-1662 



9 



25-4215 



0-1681 



0-1653 



10 



25-4215 



0-1683 



0-1655 



The mean of these results was taken as the true value and 

 the standard thus established as : 25 gms. solution =0= 0*1655 

 o-m. V.O,. 



