Wells — Complex Chlorides containing Gold. 317 



homogeneous by careful microscopic examination. In 

 some cases the crops of crystals were washed to some 

 extent by diluting the last part of the mother-liquor with 

 strong hydrochloric acid, but usually this was considered 

 unnecessary and was not done. In all cases the products 

 were carefully dried with filter paper and then in the air. 

 Further drying at 100° in all cases gave insignificant 

 losses, amounting usually to about 0.01 to 0.05%. 



In all cases experiments were made under widely vary- 

 ing conditions, but no evidence was obtained of the exist- 

 ence of more than a single compound of the same three 

 simple salts, such as occur, as the writer has shown, 2 to 

 the number of three or four with the thiocyanates of 

 cesium, zinc and silver, and also those of cesium, cadmium 

 and silver. 



Cesium-Silver- Auric Chloride, Cs 4 Ag 2 Au 2 Cl 12 . — The 

 very minute, black crystals of this salt frequently show 

 brilliant faces under the microscope, or they sparkle when 

 viewed with the naked eye, but sometimes a crop was 

 found to consist chiefly of rounded particles, probably 

 crystal-aggregates, showing no distinct faces. 



The compound appears to be stable in contact with 

 strong hydrochloric acid, but it is slowly decomposed by 

 cold water, more rapidly by the hot liquid, with separa- 

 tion of silver chloride, and frequently also of yellow 

 CsAuCl 4 . 



The following analyses of separate crops were made: 















Calculated for 



I 



II 



III 



IV 



V 



VI 



VII VIII Cs 



iAgoAu.Clu 



Cs 





33.95a 









34.39 



33.90 



Ag . . 13.60 



lVii 



13.65 



13.54 



13.47 



13.40 



13.49 13.11 



13.77 



Au . . 25.17 



24.73 



25.15 



24.84 



24.93 



24.73 



25.05 25.74 



25.17 



CI 





27.25 









26.76a 



27.16 



a By difference. 















The first three analyses represent crops produced by 

 cooling from solutions containing 20, 160 and 10 g., 

 respectively, of cesium chloride, 3 g. each of gold as 

 HAuCl 4 , 1.5 g. each of silver nitrate, and each in a volume 

 of about 1000 cc, made up of about equal volumes of con- 

 centrated hydrochloric acid and water. The other crops 

 were prepared under widely varying conditions, some of 



2 Amer. Chem. Jour., 28, 278; 30, 144. 



