276 



action of a strong quartz-lsiinp during some tew hours, appeared 

 decomposed to a detectable degree: metallic rJiodium covered the 

 walls of the (/««r^t^-apparatiis in the form of a black mirror, while 

 carbon-dioxide was set free. As the violet and blue rays are almost 

 completely absorbed by the solutions (see above), the relatively rapid 

 photochemical destruction of the molecule by rays of short wave- 

 length may be considered as (o be in full accordance with Draper's law. 



^ 7. If a solution of potassium-rliodium-oxalate be treated with 

 silver-nitrate, the siher-^oXi: \Rho (C,0,),\ A(/, is precipitated as a 

 vividly red compound, which is only little soluble in cold, somewhat 

 more in hot water, and which crystallises in long needles much 

 alike the bichromate. 



From this silver-s,&M, as well as directly from the potassium-^Si\is,, 

 by interchange with Iri-ethylenediamine-rlwdium-halogenides, complex 

 salts of the type \Rho {Eine)^\\Rlio [0^0,%, may be obtained as pale 

 yellow to orange-yellow crystalline precipitates, which are almost 

 insoluble in all kinds of solvents, as was to be expected beforehand. 



By combination of the racemic and optical ly-rtc'//iv ions, we have 

 finally obtained the following nine isomeric salts: 



\r-Rho{Eine),\ \r-Rlio {C\0,\\; \r-Rho{Eine\\ \d-Rho{C\OX\ 

 \ r-Rho {Eine\ \ \ l-Rlio (C, OX I ; { d-Rlw (Eine), \ \ r-Rho {C, 0,\ | 

 I l-Rho {Eine\ \ \ r-Rho iC\0,) |, ; { d-Rho {Eine), \ \ d-Rho {C'M, | 

 I l-Rho {Eine\ \ \ l-Rho {C\ 0,) I ; \ d-Rho {Eine\ \ \ l-Rho {C\ 6>J, i 

 and \ l-Rho {Eine), \ \ d-Rho iC\0,), \. 



^ 8. Furthermore some measurements may be i-ecorded here con- 

 cerning potassiuni-rhodiuin-malonate '. Ks\Rho{C\H^O^)t\ -\-'SH,0, a 

 new compound obtained in a way analogous to that described for 

 the corresponding oxalate, and which is now also used in fission- 

 experiments. Finally the description has been given here also of 

 potassiuni-iridium-oxalate : K^\lr {C^O^)i\ -{- ^\ H^O, of which the 

 fission into its antipodes is now being investigated also in the author's 

 laboratory. The available data prove once more plainly the full isomor- 

 phism between Rho- and /r-derivates of analogous structure. 



^ 9. Racemic Potassium-Rhodium-Malonate. 



\Rho{C,H,OX\Kz + ^H,0. 



This compound was prepared from freshly precipitated and washed 

 rhodiiun-hydro.ci/de, by boiling it during a long time with a solution 

 of potassium-bimalonate, to which some free malonic acid was 

 added. Complete solution occurs only after heating during a very 



