Cobalt complex compounds oxalato

It must be concluded, therefore, that the ligands do not become completely detached from the metal ion in isomerization reactions. Comparable results have been observed in the isomerization95 of potassium diaquodioxalatochromium(III) and the racemization96 of optically active potassium tris(oxalato)chromium(III) when no exchange with free ligand in solution occurs. Thus, although it is not practicable to take advantage of the desirable properties of individual isomers of 2 1 chromium and cobalt complexes of tridentate azo compounds because of the facility with which such compounds isomerize in solution, the technically important unsymmetrical 2 1 complexes are capable of practical application because they show little or no tendency to disproportionate in solution. 

Spectra of a variety of chromium compoimds in the +3 valence state are included in Fig. 16. The principal peak is centered at about 22-25 ev. in all cases. The CrjOa spectrum is almost identical to that of Mn02 of Fig. 5. Spectra of the oxalato complex and the ammonia complex are almost identical to spectra of the corresponding cobalt compounds of Figs. 13 and 11. 

After the resolution of 1-2-chloro-ammino-diethylenediamino-cobaltie chloride many analogous resolutions of optically active compounds of octahedral symmetry were carried out, and active isomers of substances containing central cobalt, chromium, platinum, rhodium, iron atoms are known. The asymmetry is not confined to ammines alone, but is found in salts of complex type for example, potassium tri-oxalato-chromium, [Cr(Ca04)3]K3, exists in two optically active forms. These forms were separated by Werner2 by means of the base strychnine. More than forty series of compounds possessing octahedral symmetry have been proved to exist in optically active forms, so that the spatial configuration for co-ordination number six is firmly established. 

---