Tetravalency of Oxygen, 233 



(viii.) Again, the tetravalency of oxygen cannot well be 

 dissociated from such compounds as 



K 2 O.ZnO, E.g.:— 



K 2 O.NiO, .OK 



Si0 2 . 2 Zr, K 2 0=OZn, not Zn( 



Mn0 2 . OCa, OK 



Fe 3 3 . OCa, K x 



A1 2 3 . OMg. or /0= =0=Zn 

 K 



(ix.) The numerous hydroxides, as well as hydrates *, the 

 so-called " basic salts " so numerous in the case of oxygen, be 

 it noted, and probably also the complex poly-tungstates and 

 silicates are also probably connected with this property of 

 oxygen. Prof. Carnelley's vanadates of thallium form re- 

 markable instances of the convenience of the mode of viewing 

 a salt as a combination of two oxides. 



(x.) The water of crystallization of salts may be due to this 

 association of the water molecules 



H H H 



III H 2 H 2 H 2 



—O—O—O— or 0—0—0 , 



H 



ii 



i i i 

 t i i 



where the oxygen is tetravalent or quadrivalid. The tandem 

 paper arrangement of course suggests nothing of the spatial 

 arrangement, which in all crystals is probably symmetrical. 

 The go-between influence of H 2 in Prof. Dixon's famous 



chloric acid solution used as " a polymerizer " H — 01===. It is significant 

 that there are few cases of polymerization where oxygen is not concerned. 

 It does not seern probable, however, that oxygen is tetravalent or quadri- 

 valid in cyanuric acid. The ordinary major valencies and the properties 

 of the substance suggest 









N 













hn / \h 





NC^CN 



00 CO 



and 



1 1 



NO ON 



Y 





Y 



H 





N 



Cyanuric acid. 





Paracyanogen 



Probably more ring formulae in inorganic bodies will come to light, and 

 they will affect the maypole hypothesis — as it may be called — of the 

 domination of the central polad atom. 



* Even in the case of so-called " KHO " there is more to be said for 

 K 2 H 2 2 , at least, if not (KOH) x . Ag 2 2 H 2 , though doubtful, is less mis- 

 leading than AgOH. 



