Browning and Scott — Separation of Germanium. 663 



Aet. XXXIV. — On the Separation of Germanium from 

 Arsenic by the Distillation of the Chloride in the Pres- 

 ence of a Chr ornate; by Philip E. Bkowning and 

 Sewell E. Scott. 



(Contribution from the Kent Chemical Laboratory of Yale Univ. — ccciv.) 



In a recent paper from this laboratory 1 we described a 

 modification of Buchanan's method 2 for the separation of 

 germanium from arsenic in which the modifications con- 

 sisted of a simplified form of apparatus for the distilla- 

 tion, and the substitution of potassium permanganate 

 for the current of chlorine used by Buchanan. An excuse 

 for the presentation of this modified method was to avoid 

 the necessity of the use of chlorine gas which involved 

 certain unpleasant features and a rather more elaborate 

 form of apparatus than is convenient for quick qualitative 

 tests. 



The object of the use of oxidizing agents in this process 

 is to convert any arsenic present into the arsenic condi- 

 tion and thus prevent the formation of volatile arsenious 

 chloride which would distill over with the germanium 

 chloride. The present paper is a description of another 

 modification in which chromic acid is used to bring about 

 the oxidation. Kessler 3 has used the reaction between 

 chromic acid and arsenious acid as the basis of a method 

 for the volumetric estimation of arsenious acid and one 

 of us applied the same reaction in a paper published from 

 this laboratory 4 for the estimation of chromic acid. 



The apparatus used may be briefly described as fol- 

 lows: The distillation flask consisted of a Pyrex glass 

 Erlenmeyer beaker of about 75 cm 3 capacity fitted with a 

 two hole rubber stopper. Through one of these openings 

 a bent glass tube was inserted, the other end of which 

 was placed just below the surface of about 3 cm 3 of water 

 in an ordinary test tube immersed in a beaker containing 

 crushed ice or cold water to aid the condensation. 

 Through the second opening in the stopper another tube 

 was inserted so as to have its end about 1 cm below the 

 surface of the liquid to be distilled. This tube was con- 



1 This Journal, (4) 46, 313, 1917. 



2 J. Ind. and Eng. Chem., 8, 585, 1916. 



3 Pogg. Anal., 95, 204, 1855. 



4 This Journal, (4) 1, 35, 1896. 



