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



green body is made much more difficult, and fails in many cases 

 in spite of the greatest care. 



It was found as the result of a great many experiments, that, 

 in preparing the new body, only exactly that quantity of isochlo- 

 ride of tin must be used which is necessary to convert the isoxide 

 of the copper salt into quadrantoxide. 



A solution of isochloride of tin in potash is prepared which 

 contains 50 grammes of the latter in a litre, and so much isoxide 

 of tin that 30 grammes of iodine are necessary to convert it into 

 diploxide of tin. The heat produced by the solution of the tin- 

 salt in the alkaline solution must be lowered by careful cooling. 

 To a litre of the cooled solution 300 cubic centims. of a solution 

 of blue vitriol, which contains 10 grammes of metallic copper, 

 are added, and the mixture shaken in a flask, which is almost 

 filled with it, about every five minutes, being placed in the mean- 

 while in cold water. In this case blue hydrated isoxide of copper 

 is first precipitated, which, on continued agitation, changes into 

 reddish yellow semioxide, which thereupon gradually changes its 

 colour, and after some hours becomes olive-green. After twenty- 

 four hours, the liquid above the precipitate, when supersaturated 

 with hydrochloric acid, is no longer coloured by the addition of 

 solution of iodine. 



For the washing out, at first water is used which contains hy- 

 drate of potash, and when binoxide of tin is no longer dissolved, 

 pure water is taken. After the removal of the hydrate of potash, 

 the green quadrantoxide is very slowly deposited. If then am- 

 monia is added to the wash-water, the precipitate agglomerates 

 without undergoing any other change, and may then be rapidly 

 washed out with pure water. The ammonia, which does not 

 dissolve quadrantoxide of copper, dissolves traces both of semi- 

 oxide and of isoxide of copper. 



On account of the very ready oxidizability of the quadrantoxide, 

 the washing must be performed with extreme care. Of course 

 water must be used which has been freed from air by continued 

 boiling, and has been cooled in well- closed bottles. The stopper 

 of the bottle was replaced by a doubly perforated caoutchouc 

 stopper, through one hole in which passed a tube bent below, 

 and which reached nearly to the surface of the precipitate, while 

 a short tube which ended just below the cork passed through 

 the other. Outside the cork both were bent at right angles. 

 Hydrogen gas was passed through the short tube, by which the 

 liquid was removed from the flask. Thereupon both tubes, which 

 were provided with caoutchouc tubes, were closed by pinchcocks. 

 The hydrogen apparatus was now connected with a vessel con- 

 taining boiled out water, of the same size and arranged in the 

 same manner as that in which the precipitation of the copper 



