304 Mr. J. F. Heyes on Valency, 



oxygen quadrivalid, just as in the case of "ammonium 



hydrate." 



Cl-H H x H 



ii H-N==0^ . 



Probably Professor Armstrong would agree that chlorine as 

 well as oxygen is here possessed of " residual affinity." But, 

 adopting Thomsen's formula H 3 C10, the acid liquid would be 

 HCl=OH 2 . The more open view, HC1 == OH 2 , is then 

 fairly warranted. It is this chemical unit which doubtless is 

 active in effecting the hydrolysis of the alcoholic cyanides 

 R'CN, which neither water alone nor liquefied hydrogen chlo- 

 ride, HC1, does effect. The suggestion that TeCl 4 does not 

 prove the tetravalency of tellurium is particularly interesting, 

 since the suggestions of 



CI =^P-= CI T ^ CI CI 



fM _|_a ni or even ^- e ^ 



01 ±e— U ^_^__^_ 



are likely to lead to new developments in the discussion of the 

 valency of the inorganic elements. The suggestion, on valency 

 lines, had been made in my former paper, in the case for 

 instance of T1I 3 , as 



Tl— I Tl— I 



II II or | [J 



I- 1 I— I 



and the fact that two somewhat different lines of thought 

 suggest these " closed-chain " molecules will, it is to be hoped, 

 stimulate the discussion on valency. Undoubtedly the haloid 

 compounds (except in the case of hydrocarbon derivatives) 

 must be carefully examined before it can be claimed that a 

 XC1„ " proves " the w-valent nature of X. This is especially 

 the case with n on- volatile chlorides, and is well exemplified 

 by PtCl 4 . In view of its chemical habitudes it is not easy for 

 me to believe in the symmetrical arrangement 



CI H 



] 



CI — Pt — CI which is so certain in H — C — H, 

 CI H 



or 



even to be satisfied with 



which leaves us with Hobson's choice. 



Platinum tetrachloride has the properties of an asymmetrical 

 chloride to a much greater degree than PC1 5 . It seems likely 



