Chemistry. — "-Investigations on Pasteur's Principle concerning 

 the Relation betiueen Molecular and Crystallonomical Dissym- 

 metry: V. Optically active complex-salts of Iridium- Trioxalic 

 Acid". By Prof, f! M. Jaeger. 



(Communicated in the meeting of June 21), 1918). 



§ 1. A slioit time ago I published ') some data about the 

 properties of racemic Potassium- Iridium- Oxalate: \l'^z Iv {C^ 0^)^\ -\- 

 -|- 4| /y,(>'), and on that occasion 1 announced experiments under- 

 taken witii the aim of splitting this compound into its optical anti- 

 podes. It was our purpose to gain in this way the necessary infor- 

 mation to enable us to indicate the correct configuration in s[)ace 

 of these optically active complex ions, in comparing it with that 

 attributed to the corresponding ?'A(?^/m?/i-derivatives, in consequence 

 of the arguments brought forward on that occasion. At the same 

 time I hoped to investigate in this way, what influence the 

 substitution of the central rhodiwn-SLtom in these complex ions by 

 the hoinologous iridinm-&io\n appeared to have upon the magnitude 

 and the specific character of the optical rotation and its remarkable 

 dispersion. It may be considered of importance, of course, to know 

 the relation existing between the two functions just mentioned, 

 especially in connection with our former studies on the analogously 

 constituted complex salts of cobalt and rhodium combined with 

 three molecules of ethylenediamine, where the problem arose as to 

 the true configui-ative relations between the salts of these homologous 

 metals of the eighth group of the periodic system, when rotating 

 the plane of polarisation in the same direction '). 



In the following the fission-experiments mentioned and the results 

 obtained by them are recorded in details. Thus for the first time 

 the possibility of a "partial" asymmetry *) has been proved, in the 

 case of iridium as the central atom; the series of the metals showing 



') F. M. Jaeger, Proceed. R. Acad. Amsterdam. 20. 263. (1917). 



') C. GiALDiNr, Rend. Acad. d. Line, Roma., (5a), 16. II. 551. (1907); Proceed. 

 Acad. Amsterdam, loco cit. p. 278. 



5) F. M. Jaeger, Proceed. R. Acad. Amsterdam, 17. 49. (1915); 20. 244. 

 (1917); conf. Zeils. f. Kryst. u. Miner. 55. 209. (1915). 



*) F. M. Jaeger, Lectures on the Principle of Symmetry, Amsterdam, (1917), 

 p. 2o5. 



