ipo #] Ammonia-Ethyl-Phospho-Platino-Cheokide 
Later, Rosenheim 4 published the results of an investigation 
covering practically the same ground. He found that the anal- 
ogy was real and succeeded in obtaining numerous isomers. With 
the stable ethoxy derivatives, molecular weight determinations, 
both ebullioscopic and cryoscopic, showed that while the formula 
of the 1 : 2 compound is normal, that of the 1 : 1 compound must 
be doubled, thus 
These facts show both compounds in strict accord with Werner’s 
coordination ideas, namely, that the coordination number of plat- 
inum in platinous compounds is four. Accordingly, their formu- 
las would be 
The addition of one molecule of aniline to the former, results in 
one chlorine atom becoming ionizable, but from the latter, Rosen - 
again conforming to Werner’s views. 
However, when gaseous ammonia was used instead of aniline an 
unexpected result was obtained. Two molecules of the base were 
added for each atom of platinum present, the empirical formula 
being PtCl 2 .P(OC 2 H 5 ) 3 .2NH 3 . According to Werner’s views, such 
a compound should be diionic, as represented by the formula 
PtCl, . 2P ( 0C 2 H. ) 3 and (PtCl 2 .P(0C 2 H ; ) J ) 
heim succeeded in obtaining two isomeric substances, a white and 
yellow modification, each having the formula 
