222 II. L. Wells — Caesium-Mercuric Ilalides. 



study of these compounds seems desirable since very little work 

 has been done in this direction, and therefore the present in- 

 vestigation of the caesium-mercuric chlorides, bromides and 

 iodides has been undertaken. 



The following is a complete list of the previously described 

 mercuric double-halides containing the alkali-metals and ammo- 

 nium, as far as I have been able to find them : 

 Na„Ho-CI 4 NH 4 Ho-Cl 3 RbHo- 2 Cl 5 



Rb 2 H'sCl 4 RbHcrCl 3 KH g rci 6 .2H„0 



Cs„H g Cl 4 KHo-B,- 3 



(NH 4 )„HgBr 4 NHJHgCl, . |H 2 



K 2 H g Br 4 KH ! rCl 3 . H 2 (NH 4 ) 2 Hg 3 Cl 8 . 4H 2 



Na„H<iI 4 KHo-Br,.H 2 



K 2 Ho-I 4 NaHo-Cl 3 . l^H„0 



(*H 4 ) 2 H g Cl 4 .H 2 NH 4 Hgl 3 . 1|H 2 (NH 4 ) 2 Hg 9 Cl 2n 

 K„Ho-Cl 4 .H 2 • KHo-I 3 .HH 2 

 Rb 2 R>Cl .2H 2 

 (^HJ 2 HgI 4 .3H 2 



The greater number of these arrange themselves into two 

 types with varying water of crystallization or with none. There 

 are two compounds of a third type, while the two remaining, 

 more complicated salts, stand alone. The last two were de- 

 scribed by Holmes.* 



An effort has been made to make the examination of the 

 cesium-mercuric salts very complete, but it is not safe to say that 

 every possible compound has been prepared, for negative re- 

 sults are uncertain. It will not be necessary to describe the 

 unsuccessful experiments where mixtures or uncertain products 

 were obtained. It is sufficient to say that other double-halides 

 were repeatedly looked for in every direction, and every indi- 

 cation of a new salt was followed up until a homogeneous 

 product was obtained and analyzed. 



The following table g ives a list of the salts that are to be 

 described. One of them, Cs 2 HgCl 4 , has already been prepared 

 by Godeffroy.f 



I. 



II. 



III. 



Cs 3 HgCI 6 



Cs„HgCl 4 



CsH g Cl 3 t 



Cs 3 H g Br r 



Cs;H g Br 4 



CsHgBr 3 t 



Cs 3 HgF 5 * 



Cs 2 H g I 4 



CsHgI 3 



Cs 3 H g Cl 3 Br 2 



Cs a HgCl 8 Br„ 



CsHgClBr 2 t 



Cs 3 HgBr 3 I 2 



Cs 2 HgBrJ 2 f 



Cs 2 HgCl 2 I 2 



CsH g BrI 2 



IV. 



V. 



VI. 





CsHg 2 Cl 5 



CsHg^Gl^ 





CsHg 2 Br B 





Cs 2 Hg 3 I 8 



CsHg 2 I 6 







CsHg 2 ClBr 4 



CsH g6 ClBr 10 



* Chem. News, v, 351. 





t Berichte, viii, 9. 



X These compounds an 



3 dimorphous. 





