229 



by the great soliibilily of (hese salts, indiicing iis always to work 

 with only small volumes of concentrated solutions, from which good 

 crystals are ordinarily deposited with difficulty. For the same reason 

 the transformation of the iodide into the chloride or bromide could 

 not be of any use, so that these for our purpose so very important 

 salts, could not be made use of in this case. 



Rackmic Triethylenkuiamink-Chromi-Iodide. 



On slow crystallisation this compound presents itself in the form 

 of very small, orange, apparently octahedral crystals. Crystallisation 

 must occur in the dark, because this salt, in the same way as all 

 the triaet/u/lenedianwie-chromi-sedts, becomes violet under the influence 

 of the light. Also increase of temperatnre must be avoided, because 

 the solutions change from an orange colour to a dark reddish 

 violet by the transformation into salts of the violet mjuo-type. The 

 crystals measured were not larger than a pinhead, and often they 

 were disfigured and distorted in rather a strange way. Some of 

 them showed under the microscope the appearance of fig. 2a, without 



rf^ 



Fig. 2. Bacemdc Triethylenediamine-Chromi-lodide. {-\- HJ)). 

 it being possible however to determine the MiLLERian indices of 

 their facets with complete certainty; the crystals pictured in fig. 2b 

 and 2c manifested however some measurable forms. 



Rhombic-bipi/ ram idol. 

 a:6:c- = 0',8632:J : 0,8652. 



The crystals are pseudo-tetragonal, and perfectly isomorphous 

 with the corresponding crystals oï {\\q coha Id- ^),&.\\(\ oï \\\e rhodium,-'^) 

 compound, just as we were able to prove this before in the case of 

 the trigonal chloride of this series '). The colour of the crystals was 

 orange or red; by partial loss of water of crystallisation, they 

 sometimes get locally yellow and opaque. 



1) F. M. Jaeger, Proceed. R. Acad. Amsterdam, 18. 62. (1915). 

 >) F. M. Jaeger. Proceed. R. Acad. Amsterdam, 20. 250. (1917). 

 ») F. M. Jakger, Proceed. R. Acad. Amsterdam, ibid. 247. (1917). 



