( 344 ) 



With acetic iiciil il (iinis vcllow, with ah-ohol yellowish-brown, 

 with ether hiood-red aii'l after shakiiiu' re|)eale(liy witli ether all the 

 ferric salt may be extracted. The dried ethereal solution yields on 

 evaporation, besides a little trichloroacetic acid, a reddish brown 

 crystalline mass which, on analysis, appears to have a varying 

 composition and contains about 10 7o of C, 067» of 67 and 10 to 

 11 "/„ of Fe. It always contains too little C for a normal ferric 

 trichloroacetate. Undoubtedly it is a mixture of two hexatrichloroacetato- 

 derivatives. 



A freshly prepared solution gives with A(/ A'Oj a scarcely perceptible 

 A<j 6V-reaction ; old solutions yield more Ar/ CI. Indeed, the same 

 l)henomenon is • also found with strong solutions of the acid itself; 

 it is based, as we shall see, on an oxydalion by atmospheric oxygen. 

 The solution exhibits all the reactions of the ferric-ion; with 

 potassium thiocyanafe a red, with ])Otassium ferrocyanide a blue 

 colouration; with XHjJH and alkali-hydroxides a preci|)itate of 

 colloidal Fe.J)z\ with H^S a separation of sulphur, with JK a 

 liberation of iodine; with XaMPO^ a while precipitate soluble in 

 excess of trichloroacetic acid ; with f.V//J.yS" a black precipitate of 

 FeS. The solution has an acid reaction. The analysis shows that the 

 relation of Fe -. CI in the solution is exactly 2 atoms of i^^t' to 9 atoms 

 of CI. There is no doubt that the behaviour is that of a solution 

 of a true ferric salt. 



§ 4. Beluivioui' in the lujhL The 

 couceutrated solution is soon decomposed 

 ill daylight with cvolutioji of a colourless 

 gas and separation of a heavy, white 

 crystalline precipitate \vith a [)eculiar 

 odour. 



The gas, on anah^sis, proved to consist 

 of pure carbon-dioxide. The white 

 substance was filtered off, sharply dried 

 and repeatedly recrystallised from ether 

 and alcohol. On slow evaporation the 

 crystals shown in tig. 1 were formed. 

 They are rhomb ic-bijj)/rnmidal an could 

 be proved also by etching figures. 



Axial relation -. a : b : c = 1,7992 : 

 1 : 3,1713. 



Form.s : a = |100|, predominant and 



very lustrous; ?n ^ \110\, also yielding 



p- 2_ sharp reflexes; >• = flOlj narrower and 



tn 



a 



m: 



