<i2 



Topical paratneters: y/. \\i : vi ^=: H,7467 : 7,: 797P : 4,6856. 



A distinct cleavage was not observed. 



On JlOOi, jllOj and |101j the extinction is 

 normal ; the crystals are not distinctly dichro- 

 itic The plane of the optica! axes is jOOlj; 

 pi'ohablj the />-axis is first bisectrix. The 

 apparent axial angle is great, the dispei'sion 

 has no exceptional valne ; round the rr-axis 

 it is p ^ I', with a negative character of the 

 birefringence. 



The specific weight of the crystals at 25° C. 



25° 

 was determined at d .„ ■= 1,725; the mole- 



4° 



cular volume consequently is 246,51. 



Fig. 8. 

 Dextrogyralory Trielhy- 

 lenediamineGohallinitrate 



VJIL Ritcemtc TjUteo-TrietkyleniHtiamine-Cobalti-iodidi'. 

 Formula: {6b {Aem),\ J\ -\- 1 ///> 



The compound was prepared from the corre- 

 sponding bromide by double decomposition with 

 a solution of potassium-iodide; the precipitate 

 was washed and recrystallised from warm water. 

 On slow evaporation of the saturated solution, the 

 small crystals can grow to fairly big individuals. 



Splendid, dark-red to red-brown, very lustrous 

 and clear crystals of octahedrical habit. The 

 angular values of the difterent individuals may 

 ditfer about 20' ; every crystal as a whole how- 

 ever is geometrically very well built. 



Fig. 9. 



Racemic 



Trietliylenediamine- 



Cobalti-iodide. 



lihom bicdiipyra m idn I. 

 a:h:c = 0,8700 : I : 1.7399. 



The crystals may be considered as pseudo-tetragonal, if the />-axis 

 is chosen as the pseudo-quaternary axis. 



Observed Forms: o = ill2|. and (7r=[021|, about equally well 

 developed; the faces of q are sometimes a little smaller than those 

 of 0, but both give very sharp images. Furthermore ('=:{00ij, much 

 smaller but giving good retlections; »" = {111}, very narrow and 

 somewhat dull, but quite measurable; b^[010\, extremely narrow 

 and reflecting badly; ,i' = {101j, rare and almost imperceptible. 



