246 INDIUM AND THALLIUM IN 



DETAILED CRYSTALLOGRAPHY or THE VARIOUS SALTS 



I : The series R 3 MX 6 2H 2 O 

 K 3 T1C1 6 2H 2 O 



This salt crystallises equally well in two distinct habits, 

 one of which has already been described by Fock (7). In the 

 one case the crystals are elongated along the c axis (Fig. 1), 

 and the prism faces |110j are well developed. The other 



gTICle 2H 2 (6) 

 FIG. 2 



K 3 T1C1 6 2H 2 (a) 

 FIG. 1 



habit, which was not observed by Fock, is illustrated in Fig. 2. 

 The crystals are here tabular on J001], and the faces of jllOj 

 are reduced to very narrow bands. JlOlj is in all cases small, 

 but was represented in all the crystals examined, jlllj is 

 well developed, and gives particularly good reflections. 



The following are the crystallographical data : 



System : ditetragonal bipyramidaL 



Axial constants : a : c=l : *7941. 



Forms present : jlOOj |110j jOOlj |101j Jill}. 

 S. G. =2-859 at 20. Cleavage indistinct,// J100|. 



