201 



A further study of the reaction proved this to be correct. The re- 

 action, however, is not complete, for only aliout 97 per cent, of the cuprous 

 chloride is clianged, even when the process is carried on for several months 

 and the compound shaken repeatedly with water in a stoppered bottle. 



Since these results are produced by dissolved oxygen it seemed that 

 the reaction might be hastened l»y running a current of oxygen into the 

 water containing cuprous chloride in suspension, since in this case the 

 oxygen could be replenished as fast as used up. The experiment was 

 carried out, but instead of getting a red product, a blue one was obtained. 

 This is proliably the basic cldoride described by Mallet^ as formed when a 

 current of moist air is passed over not cuprous chloride. 



This imexpected result led to a study of the action of hydrogen per- 

 oxide on cuprous chloride. The investigation is not complete: the results 

 obtained iip to date are as follows: 



When hydrogen peroxide is added to cuprous chloride, the color of the 

 salt immediately becomes a dirty green, and iipon the addition of more 

 peroxide, finally becomes a delicate blue. The compound appears very 

 flocculent. If the reaction is carried out in a bottle or tlask connected with 

 a burette, a consideraltle anunuit of oxygen can be collected. The volume 

 of oxygen evolved does not seem to bear any direct ratio to the amount 

 of cuprous chloride used. If the reaction is carried out at 100° Instead of 

 at oi'dinary temperature, the reaction seems to be the same except that 

 the evolution of the oxygen is much more rapid. The compound is evi- 

 dently a basic chloride. It is insoluble in Avater, does not change in boil- 

 ing with water, does not materially diminish in weight or change in 

 color until heated to 250,° and is easily soluble in dilute acids and in 

 ammonia. There is some evidence in favor of the following reaction: 



3 CujCl^ + 6 H^O = 2 CuaClO.OH + 2 CuOla + 5 H2O -f 3 O 



The reaction probably taking place in two stages. The blue compound 

 would seem to have the composition: 



Cu<OH 



^ 0.8 H2O 



Cu<ci 



A curious fact was ol)served in connection with this study which seems 

 to be true of other complex copper ions. If this blue compound is dis- 

 soh-ed in ammonia jind hydrogen peroxide added, a violent reaction takes 



Comp. rend. 62. 2*9- 



