1904 - 5 .] Mr Cameron on the Constitution of Complex Salts. 729 
This was first prepared by Werner,* who, on heating it to nearly 
300°, obtained the corresponding anhydride having the constitution 
The type of compound will be referred to as B. 1. 
The acid salt corresponding to the undehydrated compound will 
have the constitution 
This also, according to the same author, when heated to nearly 
300°, yields its “ anhydride,” having the formula therefore 
An alternative constitution for this anhydrous salt will be 
mentioned later. This type of salt will be designated B. 2. 
In his last paper Werner J describes a new series of salts, to 
which he gives, in the case of the ammonium compound, the 
formula (NH 4 ) 5 Cr 4 (C 2 0 4 ) 6 (0H) 5 , 2H 2 0. From this he concludes 
that the corresponding acid is H 5 Cr 4 (C 2 0 4 ) 6 (0H) 5 , 4H 2 0. It 
seems unfortunate, in view of the probable chromammonium com- 
plex, that he has chosen the ammonium compound as designating 
the type. His formula for the corresponding salt of potassium is 
K 4 Cr 4 (C 2 0 4 ) 6 (0H) 4 . If this is halved it is easily seen that the 
salt may be considered as derived from that of type B. 1 by 
elimination of potassium oxalate from two molecules, and hence 
* J. Chem. Soc., 53, p. 407. 
t Ibid. Cp. also Rosenheim and Platsch, Zeit. fur anorg. Chem., 21, p. 
11, and Rosenheim and Cohn, ibid., 28, p. 337. 
X J. Chem. Soc., 85, p. 1438. 
or O : [Cr : (C 2 0 4 .K) 2 ] 2 . 
I 
o 2 w 4 - av 
whieh is half the formula that Werner f assigns to Crofts’ red salt. 
