CRYSTALLOGRAPHICAL RELATIONSHIP 261 

 Analyses gave the following results : 



Cs. In. 01. H 2 



45-62 20-43 30-09 3-27 

 Calculated 46-13 19-94 30-80 3-13. 



(NH 4 ) 2 InBr 5 H 2 



From a solution containing NH 4 Br and InBr 3 in the 

 proportions of two to one, a fine-grained crystalline powder 

 was precipitated, brownish in colour and very soluble in water. 

 The crystals proved to be very deliquescent, and no exact 

 crystallographical measurements could be made. The habit 

 of the crystals is illustrated in Fig. 12. They are elongated 

 along the c axis, slightly tabular on the well-developed faces 

 of jlOOj, and show fairly large faces of J120J, jlOlj, and |011|. 

 The specific gravity is, as accurately as could be measured 

 under the circumstances, 3*167 at 20. 



Analyses gave the following results : 



Iu. Br. H 2 



19-70 70-11 5-92 

 Calculated 19-73 70-30 6-48. 



After standing in the solution for four days, the crystals 

 became quite opaque. The slightest changes of temperature 

 seem to affect the stability of this salt when in contact with 

 the solution at ordinary room temperatures. 



Rb 2 InBr 5 H 2 O 



From solutions in which RbBr and InBr 3 are in the pro- 

 portions respectively of 1 : 1 or 2 : 1, crystals of the above salt 

 are formed at room temperatures. The crystals are colourless, 

 fairly insoluble, and are frequently rather cloudy. They are 

 usually developed along the 6 axis, show broad faces of JlOOj, 

 large faces of |101|, and comparatively small faces of |120j and 

 Ollj (Fig. 13). 



