and Some Other Double Halides of Antimony. 455 



evidence was obtained of the existence of any double salt con- 

 taining more caesium fluoride than the one just described. 



Cmium- Antimonious Iodide, 3Csr2Sbf 3 . — It appears that 

 no compound of caesium iodide with antimonious iodide has 

 been described. The sparingly soluble chloride, SCsCl^SbCl, 

 is well known, and this was the only double chloride that 

 Remsen and Saunders* were able to prepare, although four 

 rubidium-antimonious chlorides are known. It is evident that 

 the slight solubility of caesium-antimonious chloride makes it 

 impossible to prepare concentrated solutions of the component 

 chlorides and consequently prevents the formation of salts of 

 other types. We have found that an iodide which corresponds 

 in composition to the chloride can be readily prepared. It is 

 sparingly soluble in hydriodic acid solutions, and it exists in 

 two distinct forms, one of which is brick-red and apparently 

 octahedral in form, while the other is yellow and occurs in 

 thin hexagonal plates. The octahedral salt was prepared by 

 mixing antimonious iodide and caesium iodide in rather strong 

 hydriodic acid solutions, while the yellow hexagonal salt was 

 made in much less strongly acid solutions, particularly upon 

 diluting them with water, boiling, and cooling. Two crops of 

 each form were analyzed as follows : 



Found 

 Calculated for Red salt. Yellow salt. 



Cs 3 Sb 2 I 9 . I. II. I. II. 



Caesium 22-39 23*46 22*15 



Antimony 13-47 13*91 13*19 14*36 14*52 



Iodine 64*14 62*98 63*03 



This was the only double iodide that we were able to obtain. 



There is little doubt that a corresponding bromide exists, 

 for we observed, while engaged in work with another object 

 in view, that a yellow precipitate is produced when the bro- 

 mides of caesium and trivalent antimony are brought together 

 in solution. Having overlooked the fact that the compound 

 had not been described, we neglected to analyze the product. 



Ccesium-Antimonie Halides. — So little is known concern- 

 ing the double halides of quinquivalent elements that it seemed 

 desirable to study the caesium-antimonic compounds. Setter- 

 bergf has described a single double chloride, CsCl*SbCl 6 , and 

 we have confirmed his result, but by using widely varying 

 conditions we have been unable to prepare any other com- 

 pound. Setterberg's salt crystallizes in long, colorless, trans- 

 parent needles. A crop of it gave the following results upon 

 analysis : 



* Loc. cit. f Loc. cit. 



