136 PROCEEDINGS OF THE AMERICAN ACADEMY. 



It is very unstable, giving up ammonia rapidly on exposure to the air. 

 The simplest method of determining the composition of the substance 

 would naturally be to start with a known weight of cuprous sulpho- 

 cyanate, pass in ammonia until saturated, and weigh again in sealed 

 tube, no further analysis being necessary. This method is impossible, 

 however, since, as in the case of the saturated bromine compound, the 

 cuprous sulphocyanate hardens in absorbing the ammonia and has to be 

 removed from the tube occasionally and powdered in order to insure 

 saturation. As in the case of the bromine compound, too, the results of 

 the analysis are unsatisfactory on account of the extreme instability of 

 the compound. Copper was determined in the same sample with the 

 ammonia in order to be sure of the proportion of copper to ammonia, and 

 from the proportions so obtained it seems probable that the formula given 

 is correct, in spite of the low results of the analyses. In any event, the 

 atomic ratios Cuo : (NHg)^ must be assumed to represent the minimum 

 amount of ammonia presefit in this compound. 



Analyses of Cu2(SCN)2(NH3)5. 



T. 0.5Go') gram of substance, distilled with caustic potash, required 

 83.40 cubic centimeters of a decinormal acid solution for neutrali- 

 zation. 

 II. 0.4176 gram of substance, distilled with caustic potash, required 

 57.90 cubic centimeters of a decinormal acid solution for neutrali- 

 zation. 

 III. 0.4176 gram of substance gave, on electrolyzing, 0.1571 gram of 

 copper. 



Calculated for Found. 



Cu„(SCN)2,6NH3. I. II. 



Copper 38.81 .... .... 



Ammonia 25.97 25.27 23.66 



Atomic ratio of copper to ammonia found = 2 : 5.05. 



5. DiAMMON-CuPRIAMMONIUM SULPHOCTANATE, Cu(SCN)2(NIl3)4. 



In addition to the cuprosammonium compounds just described, we suc- 

 ceeded in preparing a new c?/yonammonium sulphocyanate which contains 

 two more molecules of ammonia than that discovered by Meitzendorf.* 

 Our new substance was prepared by treating ten grams of cupric bromide 

 with about fifteen cubic centimeters of strong ammonic hydroxide, and 



* Pogg. Annalen, LVI. 63, 92. 



