74 



Dr. G. H. Bailey. 



[May 9, 



III. " Zirconium and its Atomic Weight." By G. H. Bailey, 

 D.Sc, Ph.D., The Owens College. Communicated by Sir 

 Henry Roscoe, V.P.R.S. Received April 15, 1889. 



The investigation described in the following paper was undertaken 

 primarily with a view to the redetermination of the atomic weight of 

 zirconium. In previous determinations the sulphate had been used 

 by Berzelius ( c Poggendorff, Annalen,' vol. 4, p. 126) and Mats 

 Weibull (" Om Zirkonium och dess foreningar"), the chloride and 

 oxychloride by Hermann (' Journ. Prakt. Chem.,' vol. 31, p. 77), and 

 the double fluoride of potassium and zirconium by Marignac 

 (' Annales de Chimie,' vol. 60, 1860, p. 270). The results of these 

 determinations are summed up in the following table, the relation 

 O : H = 15*96 : 1 being used in the calculations. 





Mean detei-- 

 inination. 



Maximum. 



Minimum. 



Author. 



Zr(S0 4 ) 2 



Zr0 2 



89-23 



89 -42 



89 -05 



Berzelius. 



Zr(S0 4 ) 2 



Zr0 2 



89 '255 



90-158 



88-97 



Mats Weibull. 



Zr 



014 



88-56 







Hermann. 



Zr0 2 



HC1 



89-915 



9o'-*76 



89-07 



Marignac. 



K 2 ZrF 6 



K 2 S0 4 .... 



90-31 



92-57 



89-84 



ZrG 2 



KoS0 4 



90-47 



90-97 



90 -02 



>> 



KoZrF 6 



Zr0 2 



90-6 



91*1 



89-7 





The sulphate is somewhat readily decomposed by heat, the 

 chloride and oxychloride are known to be unstable, and liable to con- 

 siderable variation of composition according to the method of prepa- 

 tions, and the conditions under which these variations of composition 

 are brought about were not understood, except in so far as the 

 researches of Troost and others have indicated the great tendency 

 which they show to pass into volatile and non-volatile oxychlorides 

 of complicated character. 



The determination is rendered difficult and unsatisfactory in con- 

 sequence of — 



(a.) The difficulty of obtaining pure zirconia, and its separation 

 from iron, titanium, and from silica. 



(&.) The tendency to form basic salts, and the hygroscopic cha- 

 racter of its salts, and their general instability. 



(c.) The tenacity with which the hydrated zirconia retains the 

 alkalies and smaller quantities of impurities in general. 



