PL. L. Wells — Cmium- and Potassium-Lead Halides. 129 



compound crystallizes in thin, white plates, which, like the 

 corresponding chloride, present considerable differences in 

 habit. Plates having a diameter of about 5 mm were some- 

 times obtained. Three separate crops of crystals were anal- 

 yzed. 



Calculated 

 Found. for CsPb 2 Br 5 . 



Caesium 14-13 14-35 14-05 



Lead 43-39 43*72 43-45 43-71 



Bromine... 42-23 42-21 42-24 



99-75 100-28 100-00 



The Caesium- Lead Iodide, and some Mixed Double- Halides / by 

 A. P. Wheeler. 



CsPb7 3 . — Under a great variety of conditions this was the 

 only double iodide that could be produced. The compound is 

 but slightly soluble in hot caesium iodide solutions, so that the 

 crops obtained were always small. It forms very slender, 

 rectangular prisms which are yellow in color. The following 

 analyses were made on separate products : 



Calculated 

 Found. for CsPbI 3 . 



Caesium.. 17-90 18-45 



Lead 28-38 27*40 28-71 



Iodine 52-83 52*57 52-84 



99-11 100-00 



Three double salts have been made by dissolving lead 

 bromide in solutions of caesium chloride. The analyses show 

 that the two salts do not combine unchanged, but that there is 

 usually an extensive exchange of halogens. Each of the 

 products must be considered, therefore, as a mixture of a 

 double chloride with the corresponding double bromide. 



C's i Pb{Cl, Br)^ — -This was produced in rhombohedrons, like 

 the chloride and bromide. Two crops were analyzed. 



Found. 



Caesium 54-65 55*50 



Lead 19-30 18-61 



Chlorine 15-89 19-90 



Bromine 9-52 4-03 



99-36 98-04 



Ratio, Br: CI 1:3-8 1:11-2 



