250 INDIUM AND THALLIUM IN 



The analyses gave the following results : 



H 2 K. In. Cl. 



6-87% 25-00% 23-26% 43-92% 



Calculated for K 3 InCl 6 2H 2 7-50% 24-40% 23-87% 44-24% 



K 3 InCl 6 1H 2 5-74% 24-86% 24-04% 45-25% 



With the exception of the potassium value, which is 

 necessarily, owing to the method of analysis, less reliable than 

 the other values, the averages all distinctly favour the formula 

 K 3 InCl 6 2H 2 O. There is in this case no possibility of dissocia- 

 tion at temperatures between 150 and 200, so that the values 

 obtained for the water of crystallisation would be abnormally 

 high for the salt K 3 InCl 6 1^H 2 O. Fock directed his attention 

 mainly to investigating whether the formula K 3 T1C1 6 2H 2 

 was correct ; although for the indium salt he obtained the 

 analysis 



H 2 Cl. In. 



5-52 45-25 23-23 

 Calculated 5-74 45-25 24-04 



it seems probable that the salt was not heated sufficiently 

 to drive off the last traces of the water of crystallisation, 

 which is liberated at a temperature considerably above 150. 

 At any rate, it seems conclusively proved that this salt con- 

 tains two molecules of water, and consequently agrees in 

 formula with the two salts already described, with which it is 

 isomorphous. 



Rb 3 TlBr 6 2H 2 



From solutions in which the relative proportions of RbBr 

 and InBr 3 were those represented by the above formula, there 

 were deposited on evaporation cubic crystals of RbTlBr 4 H 2 0, 

 and on further evaporation these were replaced by tetragonal 

 crystals of Rb 3 TlBr 6 2H 2 O. This salt crystallises in honey- 

 yellow crystals, developed on jOOlj, but not so pronouncedly 

 tabular as in the case of (NH 4 ) 3 T1C1 6 2H 2 O (Fig. 5). The faces 



