454 Wells and Metzger — Caesium- Antimonious Fluorides 



Calculated for Found. 



Cs 4 Sb 7 F 25 . T. II. 



Caesium 2S*80 28*99 



Antimony 45*47 46*02 4603 



Fluorine 25*73 24*58 24*61 



We cannot say that we are absolutely sure about the formula 

 of this apparently complicated double salt. It cannot be a 

 1 : 2 compound, for not only is it entirely distinct in appear- 

 ance from CsF'2SbF 3 , but coming as it does from a strong 

 antimony solution, the results would naturally come too high 

 rather than too low for antimony. The results vary too widely 

 from a 2 : 3 ratio to make that probable, but they approach 

 somewhat more closely the 3 : 5 ratio. The following calcula- 

 tions will show that we have selected the most probable 

 formula : 



Calculated for Calculated for Calculated for 



Cs a Sb 3 F n . Cs 3 Sb 5 F lti . CsSb 2 F 7 . 



31*86 29*75 26*28 



43*11 44-75 47*43 



25-03 25-50 26*28 



1:1 Caesium- Antimonious Fluoride, CsF*SbF 8 . — In the 

 presence of still greater proportions of caesium fluoride this 

 salt is produced by cooling the properly concentrated solution. 

 It forms square prisms, the ends of which are not usually 

 modified by any planes. Three crops gave the following 

 analysis : 



Calculated for Found. 



CsSbF 4 . I. II. III. 



Caesium 40-43 41-44 41-19 



Antimony 36'47 35*85 35*66 35-52 



Fluorine. 23-10 22-30 



2:1 Caesium- Antimonious Fluoride, 2CsF*SbF 3 . — This 

 salt is formed under a wide range of conditions when caesium 

 fluoride is present in large excess in comparison with the 

 antimonious fluoride. It crystallizes in apparently rhombic 

 prisms, which are often somewhat flattened. Four crops, 

 made under very different conditions, gave the following 

 results : 



Calculated for Found. 



Cs 2 SbF 5 . I. II. III. IV. 



Caesium _. 55*30 54*81 _.. 



Antimony 24*95 24*72 24*59 24'92 24'64 



Fluorine _ 19'75 19 42 



By the use of very concentrated caesium fluoride solutions 

 with comparatively small amounts of antimonious fluoride, no 



