250 



and indium, and also in the case of some trimalonates of these metals 1 ) : 

 many other properties, moreover, make such dissymmetrical com- 

 pounds highly promising objects for research. 



If we examine more closely the atomistic arrangement of these 

 complex salts, as deduced from Werner's coordination-theory, it 

 appears that these molecules are by no means unsymmetrical : for 

 instance, the triethylenediamine-cobalti-complex has the symmetry 

 represented in the accompanying figures, (fig. 166). It appears that 

 the stereometrical configuration has a ternary axis A 3 and three 

 heteropolar binary axes situated in a plane perpendicular to A 3 . 



Fig. 166. 

 The Symmetry of the Ions: [Me(X // ) 3 ]. 



This symmetry is that of the axial group D 3 , and, therefore, the 

 arrangement must be different from its mirror-image. 



Here we have an excellent example of a molecule composed of 

 even identical units, which possesses a rather highly symmetrical 

 configuration, and which, notwithstanding this, may be obtained 

 in two enantiomorphously related modifications, because its sym- 

 metry belongs to the groups which have only symmetry-properties 

 of the first order. The enormous rotatory power of these compounds 

 is, therefore, merely due to the non-superposable arrangement as 

 such, and to the special nature of the central metallic atom, not, 



!) F. M. Jaeger, Proceed. Kon. Akad. v. Wet. Amsterdam, Vol. 17, 1224, (1915). 

 19, (Aug.) (1917); 21, 203, (1918); Receuil des Trav. d. Chim. d. Pays-Bas, 38, 

 171, (1919); F. M. Jaeger and W. Thomas, Proceed. Kon. Acad. v. W. Amster- 

 dam, 21, 215, 227, 698, (1918); Revue generate des Sciences, 30, 298, (1919). 



