94 Wells and Walden — C cesium- Cupric Bromides. 



Caesium 



Copper 15-68 



Chlorine 30-84 



Water 4-22 







Calculated for 



Found. 





Cs 3 Cu 2 Cl 7 .2H 2 0. 



49-36 



48-96 



49.23 



15-90 



15-74 



15-67 



29-90 



3069 



30-66 



4-38 



4-41 



4-44 



99-54 



99-80 



100-00 



1:1 Ccesium- Cupric Chloride, CsCuCl s : — This is formed 

 under wide variations of conditions, up to the point where the 

 solution is saturated with cupric chloride. It can be recrystal- 

 lized from water. It forms slender hexagonal prisms termi- 

 nated by pyramids. The color is a deep garnet-red, and all 

 except very slender crystals appear black by reflected light. 

 The following analyses of separate products were made : 













Calculated for 







Found. 







CsCuCl 3 . 



Caesium 



43-67 





43-58 



43-89 



Copper 



21-16 



21-17 



21 



•06 



20-96 



Chlorine 



35-25 



35-22 



35 



•00 



35-15 



100-08 99-64 100-00 



Sheffield Scientific School, September, 1893. 



Art. X. — On the 'Caesium- Cupric Bromides / by H. L. 

 Wells and P. T. Waldek 



We have made a systematic investigation of the csesium- 

 cupric bromides, following the plan, described in the preced- 

 ing article, which was used for the corresponding chlorides. 

 Although the work has been very thorough, we have found 

 only the following two salts : 



Cs 2 CuBr 4 and CsCuBr 3 . 



These salts correspond to the two common types of cupric 

 double halides. The fact that no hydrous salts could be 

 obtained was unexpected, because it has been pointed out by 

 Kemsen* in the case of certain double halides, and it has been 

 observed by one of us in the case of the alkaline-lead halides, f 

 that the tendency to combine with water seems to increase 

 with the atomic weight of the halogen. The fact that hydrous 



* Am. Chem. Jour., xiv, 88. f This Journal, xlvi, 37. 



