RICHARDS AND WHITRIDGE. — CUPRIAMMONIUM SALTS. 463 



dissolved iu about fifty cubic centimeters of absolute alcohol. Dry 

 ammouia gas was passed into the solution, and on standing a precipi- 

 tate of cupriammonium bromide (Cu(NH3)2Br2) came down. Four 

 and a half cubic centimeters of strong propionic acid were added to 

 dissolve the precipitate, and more ammonia gas was added. Again 

 the same crystals appeared, showing that the tendency to form this 

 substance was much more decided than the tendency to form the sub- 

 stance desired. Since the addition of more propionic acid did not help 

 the matter, one and a half grams of precipitated cupric oxide were 

 added, and the whole was warmed until most of the powder had dis- 

 solved. After filtration and evaporation in the air, prismatic crystals 

 of a very strong blue color were deposited, proving to be the substance 

 sought. The crystals were washed with alcohol, and dried in the air, 

 iu which they are permanent. 0.5750 gram of the substance was 

 found to displace 0.2197 gram of toluol having a specific gravity of 

 0.8619 ; hence the specific gravity of cupriammonium propionobromide 

 is 2.255. The other properties resemble so closely those of the acetic 

 compound that it is not worth while to detail them. 



Analyses o/ Cu(NH3)2BrC3H502. 

 I. 0.1017 gram of the substance gave on electrolysis 0.0262 gram 



of copper. 

 II. 0.1061 gram of the substance gave on electrolysis 0.0270 gram 

 of copper. 

 III. 0.0825 gram of the substance yielded 0.0624 gram of argentic 



bromide. 

 IV. 0.0788 gram of the substance distilled with caustic potash required 

 6.19 cubic centimeters of a decinormal acid for neutralization. 

 V. 0.1109 gram of the substance yielded 0.0588 gram of carbon 

 dioxide upon combustion. 



