



Calculated f or 



II 



III 



Cs 4 HgAu,Cl 12 



43.41 



42.75 



43.37 



17.66 



19.72 



17.50 



38.93 



37.53 



39.13 





26.65 



27.42 



Wells — Complex Chlorides containing Gold. 321 



It forms minute, transparent, orange-red crystals, three 

 crops of which gave the following analyses : 



I 



CsCl 43.45 



HgCl 18.14 



AuCl, 38.41 



Total CI 



The principal constituents were very conveniently 

 determined by heating the substance in a Rose crucible in 

 a stream of hydrogen, gradually, and finally considerably 

 below a red heat. The loss in weight gave the mercuric 

 chloride and the chlorine combined with the gold, while 

 the residue consisted of metallic gold and cesium chloride. 

 This last mixture was treated with water and the gold was 

 collected and weighed, so that the three chlorides could 

 then be calculated. The total chlorine was determined in 

 a separate portion by the usual gravimetric method after 

 the removal of the gold and mercury by precipitation. 



The pure salt, however, was not obtained at the first 

 attempts to prepare it. Three successive crops were 

 obtained from a solution, the composition of which varied 

 from step to step on account of the removal of portions 

 of the crops and the effect of additions of mercuric chlor- 

 ide, and were approximately as follows : 



ABC 



Cesium chloride 15g. 14.5g. I4g. 



Mercuric chloride 2g. 2.5g. 3.5g. 



Gold (as HAuCIO lg. 0.9g. 0.8g. 



Hydrochloric acid a little a little a little 



Volume, roughly 200 cc. 250 cc. 300 cc. 



It is to be observed that, in addition to increased dilu- 

 tion, the principal variation of the solutions is an 

 increased proportion of mercuric choride, which, even in 

 the first case, is largely in excess of the amount required 

 to form the triple salt with the gold that is present. 



The crops obtained were in the form of small, prismatic 

 crystals which varied in color from a light reddish-brown 

 in A to a pale yellowish-brown in C, with B intermediate, 

 but the individual crystals in each crop appeared to be 

 exactly alike in color when examined microscopically. 

 These crops gave the following results upon analysis : 



