M. H. Rose on a new Series of Metallic Oxides. 367 



The corresponding compounds of the metals with chlorine, 

 bromine, iodine, cyanogen, and sulphur may be named in a 

 similar manner. 



I have used this nomenclature in what follows. . 



Quadrantoxide of Copper. 



If a solution of blue vitriol is treated with isochloride of tin 

 (protochloride of tin) to which some hydrochloric acid has been 

 added, semichloride (protochloride) of copper is obtained. If 

 the semichloride thus obtained is brought while still moist into 

 a dilute solution of isochloride of tin in hydrate of potash, the 

 white chloride is changed into a greenish body, which, however, 

 is reduced to metallic copper if a less dilute alkaline solution be 

 employed, and in excess 



If a solution of blue vitriol be added to an excess of the very 

 dilute alkaline tin solution, at first blue hydrated semioxide of 

 copper is precipitated ; but this rapidly assumes a yellow colour 

 and changes into semioxide of copper. The yellow colour of the 

 precipitate changes also on agitation, and passes into an olive- 

 green colour. The precipitate, which at first was very volumi- 

 nous, now begins to become dense and to assume a brownish-red 

 colour. It now rapidly settles on being shaken, and consists of 

 metallic copper, which, moistened with hydrochloric acid or with 

 ammonia, remains almost unchanged. But on agitation, after 

 the separation of metallic copper, the liquid does not become 

 clear rapidly, but the part of the green body which is not yet 

 reduced to oxide remains long suspended. It finally sinks also, 

 and undergoes the reduction to metallic copper. 



The green body thus obtained has an extraordinary tendency 

 to become more highly oxidized. Even with a very slight access 

 of air, it oxidizes on the surface under water into yellow semioxide 

 of copper (suboxide of copper), and finally changes into dirty 

 bluish isoxide of copper. 



By its extremely ready oxidizability on the one hand, and, on 

 the other, by its easy reductibility to metallic copper by even a 

 small excess of the dilute solution of tin, the preparation of the 



as saline compounds of an isoxide and a sesquioxide. In their solutions, 

 the sesquioxide is precipitated by weak bases, such as carbonate of baryta, 

 while the isoxide is not precipitated. Further, the weak base (the sesqui- 

 oxide) is, by the gradual addition of a strong base, an alkali for instance, 

 precipitated first, and then afterwards the strong base, the isoxide. More- 

 over by heating with a solution of chloride of ammonium, the isoxide can 

 be dissolved out of the oxides R 3 O 4 , provided they have not been strongly 

 heated, with disengagement of ammonia, while the sesquioxide remains 

 undissolved. It is only the oxide of cerium, Ce 3 O 4 , which cannot in this 

 way be decomposed into protoxide of cerium, CeO, and a sesquioxide of 

 cerium, Ce 2 O 3 , which hitherto has not been isolated. 



