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THE 



AMERICAN JOURNAL OF SCIENCE. 



[THIRD SERIES.] 



Akt. XXXYIII. — The Higher Oxides of Copper; by Thomas B. 



Osborne. 



Copper dioxide. — When copper hydroxide is treated with 

 hydrogen dioxide at a temperature near 0° C. a brown pre- 

 cipitate is formed which has been shown to contain nearly 

 twice as much oxygen as copper oxide (CuO) and when acidi- 

 fied yields hydrogen dioxide. When the temperature is some- 

 what higher a grass-green precipitate is formed which is some- 

 times yellow-green or yellow. Krtiss (Berichte, 2593, 1884) 

 has shown that the brown precipitate, when treated at 0° C. for 

 some days with excess of hydrogen dioxide and frequently 

 shaken, can be filtered and washed first with alcohol and then 

 with ether and when entirely freed from water can be dried at 

 100° C. It then has the composition of Cu0 2 , H 2 or H 2 Cu0 3 . 

 When moist Krtiss found that it began to decompose above 

 + 6° C. Above this temperature he obtained a grass-green 

 precipitate which began to decompose above +12° C. He was 

 unable to analyze this latter as it decomposed readily. 



Brodie has shown that if hydrogen dioxide be added to a 

 salt of copper in solution and then soda, a yellow precipitate is 

 formed. 



Krtiss obtained a yellow precipitate in too small quantity to 



analyze, by fusing copper oxide with sodium chloride with 



access of air. He thought this was a higher oxide of copper 



Am. Jour. Sci.— Third Series, Yol. XXXII, No. 190. — November, 1886. 

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