Chemistry. — ''Investigations into Pasteur's Principle of the 

 Connection between Atolecular and Crystallonomical Dissym- 

 metry. III. Racemic and Optically Active Complex Salts of 

 Trivalent Rhodium. By Prof. Dr. F. M. Jaegeh. 



(Communicated in the meeting of June 30, 1917.) 



§ 1. In immediate continuation of previous investigations concern- 

 ing the complex iri-ethylenediamine-S£i\ts of trivalent cobaltum ^), 

 the results of the study of tiie corresponding complex salts of trivalent 

 rhodium are communicated in the present paper, namely in so far 

 as the data already obtained possibly allow a more general discussion 

 of some problems connected with this subject. 



For the preparation of the salts investigated, we started from pure 

 rfiodiuin-trichloride. Originally Werner's method ") was followed, who 

 transformed the chloride into sodium-rhodium-chloride : Na, \Rho Cl^\ -f- 

 -\- ^2 H^O, which afterwards was dissolved in gently heated 

 ethylenediamine-hydrate. It appeared, however, that the troublesome 

 purification of the complex salt from the adhering sodiumchloride 

 may be prevented, when the rhodium-trichloride itself is dissolved 

 immediately into the base mentioned, on gently heating it with the 

 last. If some few precautions be taken, the required substance is 

 obtained from an aqueous solution immediately in very beautiful, 

 colourless crystals. It must, moreover, be remarked in this connection, 

 that a miscibility between the complex rhodium-saU and sodium- 

 chloride in the solid state, as supposed by the author mentioned 

 because of an eventually existing isomorphism of two crystal-species 

 of cubic symmetry, does in reality not occur. No such isomorphism 

 is present here, as the complex rhodium-s&M has ditrigonal, the 

 sodium-chloride on the contrary cubic symmetry. Probably only 

 occlusion or mechanical removal of the one salt by the other may 

 be the cause of the phenomenon observed. Moreover, it must appear 

 remarkable, that almost all data concerning the amount of water 

 of crystallisation present in these rhodium-sa\ts, differ exactly by the 

 number of half a molecule H^O in comparison with those of the 

 corresponding cobalti-sa^lis. As the last mentioned salts are, however, 



1) F. M. Jaeger, Proceed. Kon. Akad. Amsterdam, 17. 1217; 18. 49. (1915); 

 Zeits. f. Kryst u. Miner. 55. 209. (1915). 



2) A. Werner Ber. d. d. Ghem. Ges. 45. 1228. (1912). 



