Gooch and McClenahan — Typical Hydrous Chlorides. 373 



chlorides, Cushman* has proposed to make use of the hypothe- 

 sis of quadrivalent oxygen in a way to show linkings of 

 stronger and weaker combination. Those molecules of water 

 which are held more firmly than others are placed within the 

 molecular complex, while those molecules of water which 

 admit of easy removal without affecting the constitution of the 

 anhydrous salt are attached externally. According to Cush- 

 man, the hydrous thallic chloride may be represented by the 

 symbol 



jr H C1 = 0< 



>o=ci-o-ti< 5 



a H C1=0< 



which by placing a single molecule of water within the com- 

 plex brings to view the observed fact that at the ordinary 

 atmospheric temperatures one molecule of water is held more 

 firmly than the other three. The easy transformation of this 

 salt by the action of hydrochloric acid, as observed by Meyer,f is 

 exhibited by a comparison of the symbol with that of the 

 chlorthallic acid derived from it. 



H C1=0— g 



H— Cl = Cl-6-Tl\ TT 



For the molecule of hydrous aluminum chloride Cushman 

 makes the suggestion that the water is held in three linkages 



H H 



i i 



_0_ o— 



i i 

 H H 



within the complex, according to which the symbol would be 



H H 



i i 



o — o — CI 



/A A 



/ H H 



/ i i 



Al -O — O — CI 



\ H H 

 \ H H 



\ i i 



0—0 —CI 



H H 



*Am, Chem. Jour., xxyi, 505. fLoc. cit. 



