192 HALL AND SMITH— COLUMBIUM. [May x 9> 



the fusion in oxalic acid and comparing the color developed with 

 hydrogen peroxide with that of a titanium solution, of known 

 strength, in oxalic acid. 



Part insoluble — 0.2749 Cb 2 5 , 0.3636 Ti0 2 



Ti0 2 4Cb 2 5 soluble portion ; Cb 2 5 4Ti0 2 insoluble portion. 



2. A mixture containing 0.1270 gram K 2 TiF 6 , or .0423 gram 

 Ti0 2 and 2.5280 grams K 2 CbOF 5 .H 2 0, or 1. 1376 gram Cb 2 0., was 

 treated as above. The precipitate was nearly all crystalline. That 

 part of it insoluble in water weighed .0470 gram and contained 

 .0074 gram of TiO a leaving .0349 gram of Ti0 2 in solution (by 

 far the greater quantity). 



3. 0.2830 gram K 2 TiF 6 , containing .0943 gram Ti0 2 , and 2.7040 

 grams K 2 CbOF.H 2 0, containing 1.2168 grams Cb 2 5 , were treated 

 as before. The precipitate was chiefly crystalline. A small part 

 of it was flocculent. The part insoluble in water weighed .0740 

 gram and contained .0148 gram Ti0 2 , showing that .0795 gram 

 Ti0 2 went into solution and would be found with the bulk of the 

 columbium. 



4. 0.6790 gram K,TiF fi , containing .2263 gram Ti0 2 , and 2.2530 

 grams K 2 CbOF.H 2 0, containing 1.0139 grams Cb 2 0., were treated 

 as before. The precipitate contained a considerable amount of 

 flocculent material. The part insoluble in water weighed 0.1720 

 gram and contained 0.0710 gram Ti0 2 , leaving 0.1553 gram of 

 Ti0 2 in solution. 



The action of potassium hydroxide was also tried. It gave a 

 precipitate with columbium, soluble in an excess, and reprecipi- 

 tated by greater excess. When the solution was evaporated pearly 

 plates of potassium columbate separated out. With a solution of 

 K 2 TiF 6 a heavy precipitate was obtained, but the filtrate gave a 

 slight test for titanium. 



1. 3 1 30 gram K 2 TiF 6 , containing .4377 gram of Ti0 2 , and 1.0060 

 gram K 2 CbOF 5 H 2 0, containing .4467 gram Cb 2 5 , were dissolved 

 in 200 c.c. of water and the solution brought to boiling, when an 

 excess of potassium hydroxide was added. The precipitate obtained 

 weighed 0.5900 gram after ignition. The filtrate gave a very pro- 

 nounced test for titanium. 



Solutions of K 2 TiF 6 and K 2 CbOF 5 were studied with various 

 organic bases in the hope that differences of behavior might pre- 



