252 PROCEEDINGS OP THE AMERICAN ACADEMY 



enclosed in the brackets above. This simple compound, probably 

 owing to its great solubility, we have been unable as yet to isolate. 

 Whenever cupric chloride is treated with a great excess of concen- 

 trated ammonia water, the excess cautiously neutralized with glacial 

 acetic acid, and the whole treated with alcohol and allowed to evapo- 

 rate, great crystals of the complicated compound containing three mole- 

 cules of ammonic acetate and probably seven of water to every two of 

 cupriammonium acetochloride always separate out. The addition of 

 somewhat more acetic acid in this case constitutes the sole difference 

 between the methods of preparing this compound and the preceding. 

 In the former case an excess of ammonia was required. 



The crystals of the complex salt are of a most brilliant blue with a 

 tinge of violet, and may be obtained of almost any size. They dis- 

 solve in very small amounts of water without apparent decomposition, 

 but larger amounts of water decompose them. The new compound 

 I'eadily loses water and ammonic acetate in the air, and is converted 

 into a pale green powder, which remains to be investigated. Over 

 caustic potash in a desiccator, on the contrary, it is soon converted 

 into a pale violet powder with a very sudden loss of weight. After the 

 sudden decrease has stopped a slower decrease continues, without 

 change of color, and the composition of the powder constantly ap- 

 proaches that of the simple cupriammonium acetochloride. Its complete 

 conversion into this compound we have not yet been able to accomplish ; 

 and regarding the exact nature of the compounds which are marked 

 by the irregular decrease in weight we have as yet nothing to say. 



For analysis the crystals were pressed between filter paper. The 

 possible causes of error from decomposition on the one hand, and 

 the adhesion of mother liquor on the other, were guarded against as 

 much as possible. Nevertheless these causes of error are undoubt- 

 edly responsible for the not unreasonable variations noticeable in the 

 analytical results ; for the three specimens of crystals analyzed were 

 undoubtedly identical. 



Analyses of Complex Cupriammonium Acetochloride. 



I. 0.2404 gr. of the substance yielded on electrolysis 0.0411 gr. 



of copper. 

 XL 0.2446 gr. of the substance yielded on electrolysis 0.0419 gr. 

 of copper. 



nical meaning with regard to the structure of the molecule. Indeed, the names 

 of all the compounds described in this paper are far from satisfactory to us; 

 they would be thrown out very gladly if better ones could be found. 



