Wells — Complex Chlorides containing Gold. 259 



the hot filtrate by means of ammonium oxalate, and, after 

 hot digestion until the liquid was perfectly clear, collect- 

 ing and weighing the gold in a Gooch crucible, then acidi- 

 fying the last filtrate strongly with nitric acid, precipi- 

 tating silver chloride by means of silver nitrate, and 

 collecting and weighing the precipitate in the usual way. 

 Of course the chlorine in the first precipitate of silver 

 chloride was added to this. 



From the evidence presented here it is believed that 

 the new formula is the correct one. It is true that 

 Pollard's results agree very closely with his formula, 

 but he gives only one analysis, which may possibly rep- 

 resent selected results, while his method of prepar- 

 ing the salt for analysis, already alluded to, would 

 probably not remove any silver chloride from the salt, but 

 might remove small quantities of the other constituents. 

 In fact, it was his object to remove any gold chloride and 

 ammonium chloride that adhered to the crystals, so that 

 his results may reasonably be expected to show too much 

 silver chloride. 



The new formula varies but slightly from Pollard's, 

 and it has little advantage over his in regard to simplicity. 

 The new investigation, therefore, confirms the fact that 

 this ammonium-silver-auric chloride has a composition 

 corresponding to a rather complex formula which appears 

 without doubt to be (NHJ 6 Ag 2 Au 3 Cl 17 . 



In view of the frequent similarity of ammonium and 

 potassium salts, an attempt was made to prepare a potas- 

 sium-silver-auric chloride, but after many experiments 

 under wide differences of conditions no evidence of the 

 existence of such a triple salt was obtained. 



When cesium chloride was used, however, a triple salt 

 was easily obtained, and several other triple chlorides 

 containing cesium and gold, as well as a new double salt of 

 these two metals, have been prepared. This work will be 

 described in subsequent articles in this Journal. 



Xew Haven, Conn., 

 February, 1922. 



