215 



The analogous oxalo-diethylenediamine-chromi-szM, of which up till 

 now the fission into its active components could not be performed in 

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

 dextrogyrate oxalo-cobalt i-salt, and precipitation with alcohol; in 

 this way the right-handed isomeride was obtained, while from the 

 mother-liquor the laevogyratory salt could easily be isolated. This 

 method of fission is undoubtedly closely related to that ofOstromiss- 

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

 viously saturated at somewhat higher temperatures, supersaturation 

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



But it may appear very doubtful indeed, whether the assumption 

 of ,, stable" racemoids under these circumstances may be considered 

 justified at all, where the author himself emphasizes that the anti- 

 podes; 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 in contact with the saturated solutions. 



According to Werner, racemic potassium-rhodium-oxalate: 



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-liquor 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-super posable 

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



*) F. M. Jaeger, Proceed. Kon. Acad. v. Wet., Amsterdam, 19, 20, 264,265, 

 (1917); Receuil des Trav. des Chim. Bays-Pas, 38, 171, (1919). 



