202 HALL AND SMITH— COLUMBIUM. [May i 9 . 



amount of titanium present by comparison with the color developed 

 by known amounts of titanic acid, but this method would offer no 

 especial advantage over the hydrogen peroxide method. 



THE ACTION OF CARBON TETRACHLORIDE ON THE OXIDES 

 OF TITANIUM, COLUMBIUM AND TANTALUM. 



According to Demarcay (C. R., 104, 111) carbon tetrachloride 

 vapor passed over the ignited oxides of columbium, titanium and 

 tantalum changes them to chlorides — in the case of titanium with 

 the formation of an intermediate oxychloride. 



Lothar Meyer (Ber., 20, 681) found no action on oxide of 

 titanium. He did not try the other two. 



Delafontaine and Linebarger (Jr. Am. Ch. S., 18, 532) found 

 that oxide of columbium was changed to oxychloride, CbOCl 3 , with 

 the formation of a small amount of the chloride. In the case of 

 tantalum the oxide was not driven from the boat but remained be- 

 hind as a pasty mass, suffering no change to chloride. They sug- 

 gest this as a possible separation of the two elements columbium 

 and tantalum. 



The vapor of carbon tetrachloride was found to act slowly on 

 ignited titanic oxide at a low red heat, some chloride of titaninm 

 being continuously formed. In time all of the oxide was converted 

 into chloride. 



The oxide of columbium is readily acted upon by carbon tetra- 

 chloride even at a low red heat. The principal product is the 

 white oxychloride. Some of the yellow chloride is simultaneously 

 produced. It continues to be formed in small amounts as the oxy- 

 chloride is sublimed in the vapors of carbon tetrachloride. Colum- 

 bium oxide heated in a sealed tube with carbon tetrachloride, is 

 completely changed to chloride after several hours at 2oo°-2 2 5°. 

 The chloride dissolves in carbon tetrachloride and separates from 

 it in large, well-formed, needle-like crystals. 



The action of the vapors of carbon tetrachloride on ignited oxide 

 of tantalum is rapid, contrary to Delafontaine and Linebarger, con- 

 verting it into chloride, which can be readily freed from the carbon 

 tetrachloride and thus obtained pure. If the carbon tetrachloride 

 used contains traces of moisture oxide will be produced by the de- 

 composition of the chloride. This oxide dissolves in the fused 

 chloride and remains as a glassy mass upon sublimation of the 



