Browning and Scott — Detection of Germanium. 313 



Art. XX Y. — On the Qualitative Detection of Germanium 

 audits Separation from Arsenic ; bj Fhiltp E. Browning 

 and Sewell E. Scott. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — ccxcii.] 



Germanium, discovered in 1886 by Clemens Winkler,* is 

 found in nature most closely associated with the elements silver, 

 lead, mercury, cadmium, arsenic, tin, zinc, titanium, and nio- 

 bium. Analytically it falls into the group with arsenic and 

 tin, since its sulphide is precipitated in strong hydrochloric acid 

 by hydrogen sulphide, and this sulphide dissolves readily in 

 ammonium sulphide. The chief problem of separation, then, 

 appears to be its separation from arsenic and tin. From tin, and 

 antimony also if it is present, the separation is quite readily made 

 by heating the sulphides with animonium carbonate, which 

 readily dissolves the germanium sulphide and leaves the tin and 

 antimony sulphides practically unattacked. 



Buchananf has quite successfully separated germanium from 

 germaniferous zinc oxide containing lead, cadmium, arsenic, 

 and traces of selenium, by dissolving this oxide in strong hydro- 

 chloric acid, distilling about one-half of the volume of the 

 liquid, the distillation taking place in a current of chlorine gas 

 in order to keep the arsenic in the higher condition of oxida- 

 tion, and precipitating the germanium sulphide from the distil- 

 late by hydrogen sulphide. 



The object of this paper is to give the results of some work 

 upon the Buchanan method, and a simple modification of it de- 

 vised for rapid qualitative tests. 



Portions of zinc oxide X containing germanium, amounting 

 in all to about 425 grm., were distilled according to Buchanan's 

 method, and about 1*45 grm. of germanium sulphide was ob- 

 tained from the distillate, an amount which would be equiva- 

 lent to a yield of about •24 per cent reckoned as the element 

 germanium. This agrees closely with the percentage, '25 per 

 cent, which the oxide was said to contain. 



It was observed that the sulphide from the distillate obtained 

 below the temperature of 108° C. had a slight yellow color, in- 

 dicating the probable presence of a trace of arsenic. The sul- 

 phid from the distillate coming over between 108° C. and 116° 

 C. was in general much freer from arsenic, being practically 

 pure white. 



A simple form of apparatus was devised, consisting of a 

 small fiask fitted with a stopper through which a bent delivery 

 tube passed into a test-tube, the end being just above about 5 



*Ber. Dtsch. Chem. Ges., xix, 210. 



f J. Ind. Eng, Chem., viii, 585. 



X Furnished through the kindness of the New Jersey Zinc Co. 



Am. Jour. Sci.— Fourth Series, Vol. XLIV, No. 262. — October, 1917. 



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