Wells and Walden — Double Chlorides, Bromides^ etc. 425 



Art. LYII. — On the Double Chlorides, Bromides and Iodides 

 of Cazsium and Cadmium ; by H. L. Wells and P. T. 



Walden. 



Since the caesium mercuric halides* had been studied by 

 one of us with the result that six types of double salts were 

 found, it seemed desirable to extend the investigation to the 

 metal cadmium on account of its close relation to mercury. 

 We have, therefore, undertaken this work and as the result of 

 a systematic and very thorough search have obtained the fol- 

 lowing compounds. The salt Cs 2 CdCl 4 had already been 

 described by Godeffroy. 



3: 1 Type. 



2 : 1 Type. 



1 : 1 Type. 





Cs 2 CdCl 4 



CsCdCl 3 



Cfc'odBr. 



Cs 2 CdBr 4 



CsCdBr 3 



Cs 3 CdI 5 



Cs 2 CdI 4 



CsCdI 3 .H 2 



These cadmium salts correspond to the three types of mercuric 

 compounds which contain the largest proportion of caesium, 

 and no evidence of the existence of cadmium double halides 

 analogous to the 2:3, 1:2, and 1 : 5 types of caesium-mercuric 

 salts could be obtained. It is evident that the tendency to 

 form a variety of double halides decreases from mercury to 

 cadmium. 



Three types of cadmium double halides with alkali metals 

 and ammonium have been previously described, and a list of 

 these is as follows : 



4 : 1 Type. 2 : 1 Type. 1 : 1 Type. 



(NH 4 ) 4 CdCl, (NH 4 ) 2 CdCl 4 . H 2 KCdC), . |H 2 



K 4 CdCl 6 Na 2 CdCl 4 . 3H 2 G NaCdBr, . 2iH 2 



(NH 4 ) 4 CdBr fi K 2 CdCl 4 KCdBr, . iBfi 



K 4 CdBr 6 K 2 CdCl 4 . H 2 NH 4 CdBr 3 . ^H 2 



(NH 4 ) 2 CdI 4 .2H 2 NH 4 CdF 3 



Na 2 CdI 4 .6H 2 



K 2 CdI 4 .2H 2 



It is noticeable that, while the 2 : 1 and 1 : 1 salts in the 

 above table correspond to two types of the caesium salts which 

 we have prepared, the 4:1 type of ammonium and potassium 

 compounds differs from our 3 : 1 caesium-cadmium salts and 

 from the corresponding caesium-mercuric compounds. We 

 were entirely confident that our results were correct, for the 

 salts were well crystallized and carefully prepared for analysis, 

 and it was impossible to believe that we had obtained too little 



*This Journal, III, xliv, 221. 



