240 Mr Adie, On Bismuth. 



On Bismuth, By R. H. Adie, M.A., Lecturer of St John's 

 College. 



[Read 18 May 1903.] 



1. In a previous paper on the sulphates of bismuth (Chem. 

 Soc. Proc, Dec. 1899) the author described the somewhat unusual 

 formation of two different salts when a basic oxide Bi 2 3 is 

 dissolved in and crystallised from concentrated sulphuric acid. 

 The salts are represented by Bi 2 3 , 4S0 3 , H 2 which crystallises 

 out above 170° and Bi 2 3 , 4S0 3 , 10H 2 O which crystallises out 

 below 170° from the same solution as it cools. 



In addition, the salt represented by Bi 2 3 , 4S0 3 , 3H 2 

 crystallises out from acids of concentration represented by H 2 S0 4 , 

 H 2 and H 2 S0 4 , 2H 2 and also the salt Bi 2 3 , 4S0 3 , 7H 2 

 from acids of concentrations between and including those repre- 

 sented by H 2 S0 4 , 3H 2 and H 2 S0 4 , 5H 2 0. 



During the time occupied by this work the properties of the 

 pure oxide appeared to show slight differences from those usually 

 described as normal, among which may be noted that it appeared 

 to be increasingly difficult to precipitate the subnitrate by dilu- 

 tion alone. This impression of variability was confirmed by 

 Mr P. MacEwan from the pharmaceutical point of view. Hence 

 it appeared to be worth while to try to find out if there were an 

 unidentified constituent in the oxide purified in the usual way 

 or in the metal derived from it. 



2. An examination of the various atomic weight determina- 

 tions of bismuth confirmed this possibility. 



Thus Schneider in 1851 after purifying his bismuth by pre- 

 cipitation as basic nitrate obtained values ranging from 207*95 to 

 208*6 (mean = 208). This value was confirmed by Marignac in 

 1883. Classen in 1890 after purifying by repeated precipitation 

 as basic chloride followed by electrolysis of a solution of the 

 nitrate in nitric acid obtained values ranging from 208*797 to 

 209067 with a probable mean of 208*90, nearly one unit above 



