﻿340 T. B. Osborne — Higher Oxides of Copper. 



position had extended so far, I abandoned the analysis intend- 

 ing to try again, but have not since had time. Unfortunately 

 lack of time prevented me from working further in this direc- 

 tion, and I give my results in hope that they may be of service 

 to others in following up this subject and settling beyond a 

 doubt the composition of this interesting compound. 



When barium hypochlorite in alkaline solutions is allowed 

 to act on copper salts in the cold, a crimson red precipitate is 

 formed, which somewhat resembles the calcium cuprate just 

 described, but in many respects appears different. But little 

 seems to be known of this compound, it having been supposed 

 to be either a higher oxide of copper, the same as the precipi- 

 tate obtained with calcium, or else a corresponding barium 

 salt. In hope of being able to analyze this red precipitate, I 

 obtained results which I am entirely unable to account for and 

 publish them in the hope that some one may be tempted to 

 investigate further and reach a satisfactory conclusion. 



In order to make the red precipitate I found it best to put 

 about 50 c. c. of strong baryta water cooled to about 5° 0. in a 

 small flask, add '2 gram of copper as nitrate or chloride, and 

 then to pass chlorine gas through the solution till the color 

 changed to a blackish green, then to add 100 c. c. of baryta water 

 of 5° C, and after shaking vigorously let stand about half an 

 hour. The precipitate which forms on adding the 100 c. c. of 

 baryta water changes from a blackish green to a dark dirty red 

 and then slowly to a bright crimson. This precipitate settles 

 very slowly and evolves a gas gradually, and even when kept 

 cold will decompose on standing a few hours. All my attempts 

 to wash it failed utterly. On a filter paper it decomposed 

 rapidly. When washed with cold baryta water by decantation, 

 no apparent change beyond the very slow evolution of gas 

 could be seen until several times decanted, when suddenly the 

 crimson color would disappear and a dirty pinkish precipitate 

 remain. I had to abandon my attempts at decanting more than 

 once or twice and endeavored to determine the composition of 

 the precipitate by decanting once, letting the precipitate settle, 

 and then drawing off 50 c. c. of the clear solution and 50 c. c. of 

 the solution containing the precipitate and analyzing each, 

 the difference representing the precipitate. 



No. 1. 

 Precip. + sol. 

 I. 



II. 



Precip. + sol. 



Sol. 



DifE.=p. 



CuO = '2905 







= -2905 



BaO -6965 



•6669 



•0296 



O -0269 



•0267 



•0002 



CI -0268 



•0245 



•0023 



CuO -3422 







•3422 



BaO -7025 



•6657 



•0368 



