258 INDIUM AND THALLIUM IN 



The crystals give up their water of crystallisation very 

 slowly on heating. The analyses of the salt gave the following 

 result : 



In. CL ELjO 



32-70 49-63 5-30 



Calculated 33-19 51-21 5-20. 



Rb 2 InCl 5 H 2 



A solution which contains RbCl and InCl 3 in the proportion 

 of two molecules of the first to one molecule of the second 

 deposits on evaporation well-formed crystals of the above 

 composition. This salt is sparingly soluble, and medium-sized 

 crystals can be grown without difficulty. In habit the crystals 

 are more or less tabular on jlOlj, and are usually elongated 

 along the b axis. They show large faces of JlOlj, and fairly 

 well-developed faces of J120J; (01 1} and |100j are small, but 

 are represented on all the crystals investigated. The general 



Rb 2 InCl 5 H 2 O 

 FIG. 10 



habit is shown in Fig. 10. The reflections are good from all 

 faces except from those of [101|, which frequently give 

 multiple reflections. Dispersion is high. Practically all the 

 crystals are twinned, the twinning plane being jllOj ; the two 

 individuals of the interpenetrating twin cross at an angle of 

 88 22'. The interpenetrating twin, looked at from above, 

 bears a marked resemblance to the iron cross of pyrites, the 

 J120J faces of the second individual appearing through the 

 large faces of JlOlj on the first. 



