Chemistry. — " Investigatioiis o)i. Pasteur's Principle concerning the 

 Relation between Molecular and CryHallonomical Dissymmetry : 

 VI. On the Fission of Potassium- Rhodium- Afalonate into Its 

 Optically-active Components.'' By Pi-of. F. M. Jaeger and 

 William Thomas. B. Sc. 



(Communicated in the meeting of June 29, 1818). 



1. Some time ago one of us') described the ci-ystalform oï racemic 

 Potassium- Rhodium- Malonate: Ks\Rho{CsH,0^)f\-{-3H,0, and hinted 

 at the possibility of separating this salt into its optically-active com- 

 ponents. In the following we are now able to describe the results 

 of the respective experiments, which have led to a positive result, 

 and to give a review of the higiily remarkable rotation-dispersion of 

 these new salts. 



The racemic salt nesessary for these experiments was prepared in 

 the following way. A 3 Vo'Solution of pure Na^Rho CI , -\-dH^O was 

 heated to 40° C, and then precipitated by means of a JO "/o solution 

 of caustic potash, so much of the base being added, that the liquid 

 showed a feeble alkaline reaction. The precipitate is separated 

 from the excess of potash as well as possible by repeated decan- 

 tation in high cylindrical vessels; it settles down extremely slowly, 

 so that this operation takes much time. Then tiie precipitate is 

 brought into a round bottom distilling-flask and heated under a 

 reflux-cooler some forty hours with a solution of the calculated 

 amount oi potassium-bimalonate : KHC^H^O^, and some free ??m/6'?i/c 

 acid, until the precipitate no longer diminishes in quantity. The 

 red coloured liquid is then filtered, and concentrated on the water- 

 bath : on slow evaporation at room-temperature there soon appear 

 red flat crystals of the complex malonate, which are once more 

 recrystallised from water for purification. The residue in the flask 

 is again changed into the complex sodium-rhodium-chloride: 

 Na^RhoClt -\- ^H,0 in the usual way, and afterwards precipitated 

 as described in the above. 



^ 2. After a series of attempts we succeeded in separating this 

 salt, which crystallises in beautiful monoclinic crystals '), into 

 its optically-active components by the aid of its cinchoni?ie-s&\t. 



i; F. M. Jaeger, Proceed. Kon. Acad. Amsterdam, 20. 276. (1917). 

 ') loco citato, p. 277. 



