and Iodides of Caesium and Zinc, etc. 



433 



3:1 Ccesium-Zinc Chloride, Bromide and Iodide, Cs z ZnCl 6 , 

 Cs s Z?iBr 5 and Cs 3 ZnI a . — Each of these salts crystallizes in 

 colorless prisms, apparently monoclinic in form. They are 

 produced by making aqueous solutions of the constituents in 

 the calculated proportions, but in the case of the iodide, with 

 these proportions the 2 : 1 salt may form if the solution is too 

 dilute. The salts under consideration continue to form as the 

 relative amounts of caesium halides are increased until the 

 latter crystallize upon them. This indicates that no double 

 salts with a higher proportion of caesium exist. The iodide 

 forms under rather wider limits of conditions than the other 

 two salts and it usually forms larger crystals. All the salts 

 require concentrated caesium halide solutions for their prepara- 

 tion, and the chloride especially is difficult to obtain in suffi- 

 cient quantity for analysis unless as much as one or two hun- 

 dred grams of the caesium halide is used. The following 

 analyses were made, all of which represent separate crops. 



Calculated for 

 Found. Cs 3 ZnCl 5 . 



Caesium 62-46 62*20 



Zinc 10-08 9*80 10-13 



Chlorine 27*43 27*34 27*67 



Calculated for 

 Found. Cs 3 ZnBr 5 , 



Caesium 47*12 46-18 



Zinc 732 7-54 7'87 7*52 



Bromine 45*91 46*54 45*85 46-30 



Calculated for 

 Found. Cs 3 Znl 5 . 



Caesium 36*54 36*20 36-08 36*30 



Zinc . 5*77 5*95 5*74 5*92 



Iodine 56*89 57*16 57'78 



2:1 Ccesium-Zinc Chloride, Bromide and Iodide, Cs 2 Z?iCl A , 

 CsJZnBi\ and Cs 2 ZnI v — These salts form colorless plates, de- 

 creasing in size from the iodide to the chloride. They are all 

 readily produced when larger proportions of the zinc halides 

 are used than are necessary for the 3 : 1 compounds and they 

 recrystallize from water unchanged. They continue to form, 

 through a wide range of conditions, as more of the zinc 

 halides are added until the solutions become syrupy. In 

 extremely syrupy solutions crystals of a different appearance 

 were noticed, but on account of the nature of these solutions, 

 no satisfactory analyses of these products could be made. It 

 seems probable that they were 1 : 1 salts, analogous to the cad- 

 mium salts of that type. 



The following analyses of separate crops were made : 



