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



with sodium hydroxide gives off ammoniacal vapors, thus pointing 

 to nitride of columbium, likely Cb 3 N 5 . 



Columbium chloride containing some sulphur monochloride was 

 treated with benzene. The sulphur monochloride dissolved out, 

 while the columbium chloride was decomposed, leaving an insol- 

 uble gummy mass. Chloroform dissolved the chloride readily, but 

 the solution seemed to undergo decomposition on warming and 

 evaporating, as the liquid became brown and a brown powder sep- 

 arated. No crystalline product could be procured. 



The chloride is also soluble in alcohol. In the cold there is no 

 decomposition. On warming and concentrating the solution acid 

 vapors were given off, due perhaps, as H. Rose has suggested, to 

 the formation of ethyl columbate. That there is no decomposition 

 in dilute solution is shown by the formation of the compound 

 CbCl 5 (C 5 H n N) 6 , which was obtained on adding piperidine to the 

 alcoholic solution (Zeit. anorg. Chem., 36, 100). Other bases, 

 such as aniline, pyridine, etc., gave addition products which were 

 insoluble in the solvent. 



The best solvent for columbium chloride is carbon tetrachloride. 

 In this solution reactions should take place, as they do with other 

 chlorides, in aqueous solution ; also double chlorides, analogous 

 to the double fluorides, should be formed by bringing together 

 solutions of the chlorides in carbon tetrachloride. 



POTASSIUM FLUOXYPERCOLUMBATE. 



When potassium columbium oxyfluoride is dissolved in three 

 per cent, hydrogen peroxide the solution acquires a yellow color. 

 When a saturated solution cools a pasty mass of crystals separates. 

 These are very hard to free from mother liquor. When dry they 

 have only a faint yellow tint. On dissolving in water, containing 

 hydrogen peroxide, the solution again becomes yellow in color. 

 The salt obtained in this way is potassium fluoxypercolumbate of 

 the following composition — K 2 Cb0 2 F..H 2 0. 



METHOD OF ANALYSIS. 



The potassium was determined as sulphate and the columbium 

 as oxide in the usual way, that is, by expelling the fluorine with 

 sulphuric acid, boiling with water, filtering out the insoluble 



