300 



No distinct cleavabiiitj was found. 



In contrast witii the Avater-containing crystals of the trans-(\ev\' 

 vative, these crystals do not manifest any trace of change. They 

 are distinctly dichroitic : on [010] orange-red for vibrations parallel 

 to the c'-axis, for such as are perpendicular to them -. blood-red. The 

 angle of extinction on /; includes 33° with the direction of the 

 c-axis, in the quadrant of the acute angle a : c. 



§ 10. Trans-Dinitro-diethylenediamine-Cobalti-Nitritk [Croceo-ssdt). 



f [Linejt ) 



Big, splendidly developed, dark brown 

 crystals which, however, soon lose 

 their water of crystallisation, becoming 

 gradually orange-yellow, most rapidly 

 on the faces of the prism. 



Monoclinic-prismatic. 



a: 6:C = 1,0458: 1:1.7995; 



/? = 68° 337,'. 

 Forms observed: m =[110], predo- 

 minant and very lustrous; 0=1 [111], 

 large and giving good reflexes, like 

 c = [001], which is much smaller than 

 m; oi =: [225], very small, and often 

 absent. Notwithstanding the different 

 angular values there exists a striking 

 analogy in aspect and development 

 of these crystals, and those of the 

 anhydrous cw-derivative. 



Fig. 8. 

 Trans-Dinitro diethylenediamine- 

 Gobalti-Nitrite. 



