322 Wells — Complex Chlorides containing Gold. 



Differences Differences 

 ABC A— B A— G 



CsCl 40.51 39.43 38.37 + 1.08 + 2.14 



HgCl 2 ..41.59 52.58 60.40 —10.99 —18.81 



AuCl 3 17.90 7.99 1.23 + 9.91 + 16.67 



It is evident from these results that these products 

 probably represent mixtures of a compound containing 

 gold with another containing none of that metal, and it is 

 not difficult to calculate from the differences the composi- 

 tion of the compound without gold. The results of this 

 calculation are as follows : 



Calculated for 

 From A-B From A-C CsHgCl 3 



CsCl 38.57 38.21 38.26 



HgCl 2 61.43 61.79 61.74 



The agreements with the calculation for CsHgCl 3 are 

 remarkably close, and there can be no doubt about this 

 constituent of the mixture. This double salt was 

 described 6 in this laboratory long ago, together with 

 Cs 3 HgCl 5 , CsHgCl 5 and CsHgsCln, all of which yield this 

 salt upon recrystallization from water. It was found to 

 be soluble only to the extent of 1.426 parts in 100 of water 

 at about 17°, and since it is very probably still less soluble 

 in cesium chloride solutions it is evident that any consid- 

 erable excess of mercuric chloride should be avoided in 

 the preparation of the triple salt. 



The evident isomorphism of the double salt CsHgCl 3 

 with the triple salt Cs 4 HgAu 2 Cl 12 , as shown by the uni- 

 form habit and colors of the crystals of their mixtures, 

 makes it appear possible, unless this isomorphism is con- 

 sidered as merely accidental, that a multiple formula, 

 Cs 4 Hg 4 Cl 12 , should be given to the double salt, from which 

 the triple salt may be derived by the replacement of Hg" 3 

 by Au'" 2 . 



Another complication was encountered in the further 

 study of this triple salt, for with various experimental 

 solutions the products obtained varied remarkably in 

 color. Some of them were bright orange-red, some were 

 dark brown or nearly black, although transparent, while 

 others were very black and opaque. These differently 

 colored products showed little or no variation in composi- 

 tion, and the cause of the changes in color was not under- 



c H. L. Wells, This Journal, 44, 225, 1892. 



