458 PROCEEDINGS OP THE AMERICAN ACADEMY. 



XIX. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE. 



ON THE CUPRIAMMONIUM DOUBLE SALTS. 



SECOND PAPER. 



By Theodore William Richards and Andrew Henderson 



Whitridge. 



Presented May 9, 1894:. 



The continuation of the study of the cupriammonium double salts, 

 begun in 1891,* has led to the preparation of the following new 

 compounds : — 



(1.) Cu(NH3)2CICH02. 



(2.) Cu(NH3)3BrC.,H30o . HjO. 



(3.) Cu(NH3)2BrC3H50.,. 



(4.) Cu(NH3)2BrC3H503. 



(5.) Cu(NH3)2ClC3H503. 



(1.) Cupriammonium Formiochloride, Cu(NH3)2ClCH02. 



The bromide corresponding to this chloride has been described 

 already by Richards and Shaw. The chloride itself was obtained at 

 the same time by these experimenters, but only in an impure state, 

 and the present problem was to determine the conditions necessary 

 for the preparation of the substance in a state of purity. 



If any considerable amount of water is present in the materials, 

 basic salts of copper are certain to be precipitated, and to contaminate 

 the preparation. On the other hand, the slight solubility of cupric 

 formiate and cupriammonium chloride in alcohol makes it difficult to 

 avoid the admixture of these substances with the desired compound, 

 if alcohol is used in the anhydrous condition. 



* Theo. W. Richards, Berichte d. d. ch. Gesell., XXV. 1492; T. W. Richards 

 and H. G. Shaw, These rroceedinp.s XXVIII. 247. 



