414 Wells — Complex Chlorides containing Gold. 



Art. XXXVIII. — Some Complex Chlorides containing 

 Gold. III. A. New Cesium-Auric Chloride; by Horace 

 L. Wells. 



[Contribution from the Sheffield Chemical Laboratory of Yale University.] 



This salt, Cs 5 Au 3 Cl 14 , was first obtained accidentally 

 by cooling a very concentrated solution of cesium chloride 

 containing comparatively little auric chloride. It may be 

 prepared from practically neutral solutions, but it is best 

 to use strong, or even concentrated, hydrochloric acid 

 as the solvent, since this acid makes the salt more stable, 

 so that, in its presence, far less concentrated solutions of 

 cesium chloride will give this red salt instead of the usual, 

 yellow double salt CsAuCl 4 . 



The new compound forms very minute, deep red 

 crystals, which are quickly decomposed by water, usually 

 with the formation of the yellow double salt as a pre- 

 cipitate. 



It appears to be the only known auric double chloride 

 not derived from hydrochlorauric acid, HAuCl 4 , and to 

 be a unique type among the double halides of the trivalent 

 metals in general. It was overlooked by Wells and 

 Wheeler, 1 who made an investigation of the cesium and 

 rubidium chloraurates and bromaurates, in this labor- 

 atory, and found only CsAuCl 4 and 2CsAuCl 4 .H 2 Q as the 

 double cesium chlorides. Evidently they did not carry 

 their experiments to a sufficient excess and concentration 

 of cesium chloride. 



Four crops of the new salt were analyzed at first. 

 They were prepared by cooling solutions containing in 

 each case about 180 g. of cesium chloride and 1 g. of gold, 

 as HAuCl 4 , in volumes of 300, 500, 700 and 500 cc., respec- 

 tively. The first three solutions contained a moderate 

 amount of hydrochloric acid, while the last one was nearly 

 neutral. The results of these analyses, where the crops 

 were not washed in any way and were dried on filter- 

 paper, in the air, and finally at 100°, were as follows : 













Calcul 



ated for 





I. 



II. 



III. 



IV. 



Cs T Au 4 Cl 19 



Cs 5 Au 3 CI 



CsCl . 



..49.16 



48.75 



48.72 





49.24 



48.02 



AuCl 3 



. 50.10 



50.45 



50.57 



50.60 



50.76 



51.98 



1 This Journal, 44, 157, 1892. 



