209 



Tin* analogous oxalo-dicthylenediamine-chromi-*.\\\ of which up till 

 MI\V tin t'i>-.ion into its active components could not be per formed in 

 .my other way, was readily separated by the addition of 10% of the 

 gyrate oxalo-cobalti-sa.lt, and precipitation with alcohol; in 

 this way the- righthanded isomeride was obtained, while from the 

 motlnT-li(|uiil the laevogyratory salt could easily be isolated. Thi-. 

 met hod of fission is undoubtedly closely related to that of Ost ro m i > - 

 It-nsky and Gernez, as by the rapid cooling of the solutions pre- 

 viously saturated at somewhat higher temperatures, supersatunition 

 will also be produced in this case to a greater or smaller degree. 



Mnt it may appear doubtful whether the assumption of ..stable" 

 racemoids under these circumstances may be considered justified at 

 all, where the author himself emphasizes that the antipodes must be 

 ,,less soluble" than the racemic compound: this, in fact, seems to 

 exclude any other view than that the racemoid is really the less 

 stable solid phase with respect to the saturated solutions. 



According to Werner, racemic potassium-rhodium-oxahtie: 



would be separated into both its active components by spontaneous 

 crystallisation if a solution of the salt saturated at its boiling point, 

 and after being rapidly brought to 90 C, is slowly cooled until room- 

 temperature is reached. Two kinds of crystals which would be enan- 

 tiomorphously related, would be deposited from the solution. After 

 selection under the microscope, a crystal of each kind, if it simply 

 remained in the saturated mother-liquid at room-temperature for a 

 long time, would slowly grow to rather large individuals. 



However these statements must, in the present writer's opinion/be 

 considered erroneous. For the solubility of the active components is 

 appreciably greater at room-temperature than that of the racemic 

 salt, the latter being therefore the stabler phase under the prevailing 

 conditions. Indeed, it was shown by direct experiments 1 ), that 

 a crystal of the active components, if brought into the saturated or 

 slightly supersaturated solution of the racemic compound, will 

 rapidly disintegrate and afterwards disappear completely. From 

 the solution, however, only the triclinic crystals of the racemic 

 compound can be obtained, which by their accidental development 

 can eventually make the impression of being non-superposable 

 with their mirror-images. Obviously the crystal-forms reproduced 



F. M. Jaeger, Proceed. Kon. Acad. v. Wet. Amsterdam, 19. June, (1917). 



