28 H. L. Wells — Discussion of Triple Salts. 



occurred with metals of corresponding valency is remark- 

 able. A list of these thiocyanates, according to their 

 types, is as follows : 



2:1:2 salts. 

 Cs 9 MgAg 2 (SCN) 6 .2H 9 Cs 2 CaAg 2 (SON) 6 .2H,0 



Cs 9 MnAg 9 (SCN) 6 .2H.,0 Cs„NiAg 2 (SCN) 6 .2H,0 



Cs 2 CoAg 9 ( SCN) 6 .2H o 0' Cs 2 NiCu' 2 (SCN) 6 .2H 2 



Cs 9 CdAg 9 (SCN) 6 .2H o RboBaAg",(SCN) 6 .2H 2 



Cs 2 CdAg 2 (SCN) 6 



3:1:2 salts. 

 Cs 3 SrAg 9 (SCN) 7 Cs 8 BaAg„(SCN) 7 



Cs 3 SrCu' 2 (SCN) 7 Cs 3 BaCu' 2 (SCN) T 



4:1:2 salts. 

 K 4 BaAg 2 (SCN) 8 .H 2 Rb 4 BaAg 2 (SCN) s .H 2 



1:1:1 salt. 2:1:1 salt. 



CsZnAg ( SCN ) 4 .H 2 Cs 2 ZnAg ( SCN) 5 



1 • 1 • 3 salt I • 2 • 3 salt 



CsCdAg 3 (SCN) 6 .2H 2 6 CsZn 2 Ag 3 (SCN) 8 



2:1:4 salt. 1:2:4 salt. 



Cs 2 CdAg 4 ( SCN) 8 .2H 2 CsZn 2 Ag 4 ( SCN) 9 



In most cases only a single triple salt could be pre- 

 pared from the same three simple thiocyanates, but Rb, 

 Ba,Ag gave two of them, one of which is analogous to 

 the K,Ba,Ag salt, while neither of them corresponds to 

 the single Cs,Ba,Ag compound. With Cs,Zn,Ag and Cs, 

 Cd,Ag four different salts were prepared in each case, 

 but there is no correspondence between these compounds 

 of such closely related metals as zinc and cadmium. It 

 is a curious circumstance also that while two of the cad- 

 mium salts, as hydrous and anhydrous forms, belong to 

 the most common, 2:1:2, type, the other two cadmium 

 compounds and all four of the zinc salts are unique in 

 type, and thus comprise six out of the nine kinds of 

 formulas shown in the above table. 



A series of analogous triple nitrites was described in 

 this laboratory by Professor George S. Jamieson. 7 

 Their formulas are as follows : 



6 Described as Ca t Cd 8 Ag 1 o(SCN)2o.6H 2 0, which varies but little from the 

 simpler formula given here. 



7 Amer. Chem. Jour., 38, 614. 



