ISO HALL AND SMITH— COLUMBIUM. [May i 9l 



second fraction contained about 3-4 grams of oxide from each 100 

 grams of double fluoride taken. These ten last fractions were com- 

 bined and dissolved in hydrofluoric acid, 15 grams of potassium 

 hydroxide added, then dilute ammonium hydroxide until slightly 

 acid, and the precipitate filtered out. It was marked "A." Am- 

 monium hydroxide was then added to the nitrate until litmus 

 showed the reaction to be just neutral. The precipitate was 

 designated "B." "C" was obtained in the filtrate from "B" 

 by adding a large excess of ammonium hydroxide. It (C) pre- 

 sumably should contain most of the titanium from the 1,000 grams 

 of double fluoride taken. The oxide actually present in it was 

 changed to double fluoride by dissolving in hydrofluoric acid and 

 adding potassium carbonate. The first crop of crystals was ob- 

 tained from strong hydrofluoric acid. It recrystallized from the 

 same in needles. These were analyzed : 



0.6954 gram of sample gave 0.3018 gram oxide and 



0.3900 gram potassium sulphate, 

 .3018 : .3900 :: x/2 : 174, x= 269.3. 



Calculated 

 K,,CbF 7 . Found. 



Oxide 57-05 56.09 



K 2 S0 4 43-93 43-40 



The sp. gr. of the oxide equaled 4.45. 0.3 gram of it showed 

 the presence of the equivalent of .0025 gram of Ti0 2 , or 0.83 

 per cent. 



The needles from "C," not taken for analysis, and the mother 

 liquor were combined and evaporated to dryness on a water bath 

 to expel the excess of hydrofluoric acid. This was repeated once. 

 The solution of the salt was then fractionally precipitated with 

 amonium hydroxide, the fractions up to the point where litmus 

 showed a slightly alkaline reaction being discarded, when the fil- 

 trate from them was made strongly alkaline with ammonium hy- 

 droxide. The precipitate obtained was changed to its potassium, 

 double fluoride. About 2.5 grams of the double salt were got. 



Analysis : 



0.7248 gram of sample gave 0.3014 gram of oxide and 

 0.4205 gram of K,S0 4 

 0.3014 : 0.4205 :: x/2 : 174 .v= 249.4. 



