﻿336 T. B. Osborne — Higher Oxides of Oopp 



", 



peroxide with sodium chloride cannot be the same as Brodie's 

 as suggested by Kriiss, for the latter's compound must have 

 been anhydrous while Brodie's is most probably a mixture of 

 copper hydroxide with copper dioxide. When boiling a small 

 amount of copper dioxide with water I obtained after a few 

 minutes a bright yellow precipitate which did not decompose 

 even when boiled for sometime, nor on standing some days in 

 a test tube in the laboratory. There was too little to analyze 

 and I could not obtain it again. This may have been the 

 same oxide as Kriiss obtained by fusing copper oxide with 

 sodium chloride. Lack of time prevented me from further 

 investigating this compound. 



Copper sesquioxide. — Crum (Liebig's Annalen, lv, p. 213) de- 

 scribed a higher oxide of copper which he obtained by mix- 

 ing with one pound of bleaching powder, solution sp. gr. 1*06, 

 50 grains sifted calcium hydroxide, and then adding to the solu- 

 tion cooled to 0° C. 20 grains of copper oxide dissolved in 70 

 grains of nitric acid sp. gr. 1*3. In this way he obtained a 

 blue solution from which a black precipitate separated on 

 standing some hours. This precipitate evolved oxygen and 

 floated on the top of the solution for sometime. After twenty- 

 four hours or more the oxygen ceased to come off and the pre- 

 cipitate settled to the bottom in a dense condition. This 

 precipitate, when finely divided, had a crimson tinge and a 

 brighter red color when rubbed with a rod to a thin layer on 

 glass. When soda was used instead of the suspended lime, he 

 obtained a rose-red precipitate which would not settle. Crum 

 considered the precipitate obtained with lime the same as that 

 obtained with soda and attributed the difference in color to a 

 difference in subdivision. He succeeded in washing the dense 

 black precipitate by decanting with cold lime water and found 

 that it contained no CI and an excess of oxygen. 



He made several determinations of the ratio between the 

 copper and the oxygen by taking a weighed amount of copper 

 oxide, treating it as described and measuring the amount of 

 oxygen evolved on acidifying. For 20 grains of copper oxide 

 he obtains in six analyses, I 1-875, II 1*886, III 1*748, IV 1-915, 

 Y 1*795, VI 1*747 grains of oxygen. The mean is 1*828 grains. 

 Cu 2 3 would require 1*98 grains. By re-calculating these results 

 so as to show the ratio between the oxygen found and the cop- 

 per oxide I obtained the following numbers : 



I. For one atom of oxygen, 2*14 copper oxide. 

 II. " " " 215 " 



III. " " " 2*30 " 



IV. " « " 2*11 " 

 V. " " " 2'24 " 



VI. " " " 2-30 " 



