201 



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

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

 chloride is changed, 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 by running a current of oxygen into the 

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

 oxygen could 1)e replenished as fast as used up. The experiment was 

 carried out. but instead of getting a red product, a l)lue one was obtained. 

 This is proltably the basic chloride described by Mallet^ as formed when a 

 current of moist air is passed over hot cuprous chloride. 



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

 oxide on cuprous chloride. The investigation is not complete; the resiilts 

 obtained up to date are as follows: 



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

 salt immediately liecomes a dirty green, and upon the addition of more 

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

 flocculent. If tlie reaction is carried out in a bottle or flask connected with 

 a burette, a considerable amount 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 ordinary 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 water, 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 Cu^CU + 6 H^O = 2 Cu.ClO.OH + 2 CUOI2 + 5 K^O -f 3 O 



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

 would seem to have the composition: 



Cu<OH 



^ 0.3H.,0 



Cu<ci 



A curious fact was o1)served in connection with this study which seems 

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

 solved in ammonia and hydrogen peroxide added, a violent reaction takes 



' Comp. rend. 62, 049 



