THE COMPLEX FERRI-MALONATES. 6 



The salt is soluble in water, insoluble in alcohol. Its aqueous 

 solution is unstable, the green colour soon changing into brown 

 even at an ordinary temperature. The change is, however, by 

 no means complete, as the brown solution, when evaporated spon- 

 taneously, leaves the green crystals mixed with a brown amorphous 

 substance. Judging from the fact that the solution becomes very 

 stable on addition of sodium malonate, the instability of the salt 

 in an aqueous solution may be ascribed to the hydrolysis which 

 all ferric salts are liable to undergo. Thus — 



.OOÜ.CH,.COO'" 

 Fe— OOC . CHo . COO + SILO 

 "^000 . CHo . COO 



/COO" 

 Fe(OH)3 + 3CH.< H-SH* 



\coo 



It is unstable towards acids and alkalies. The former convert 

 the iron into the simple ionic state, and the latter, when slightly 

 in excess, precipitate it as ferric hydroxide. 



Potassium ferri-malonate. 



This was prepared from potassium malonate and ferric 

 chloride in a manner quite analogous to that in the case of the 

 sodium salt. The analytical results were as follows : 



I. 0-2267 gram substance gave 0-0287 gram water (by loss). 



