of the Metallic Oxides. 91 



The true oxides RO^ which are really comparable with the 

 known chlorides KC1 2 *, are for the most part quite unknown. 

 We only have the polymeric oxides w(ROa,), in which n is a 

 large number. To make this dear, we may take an example 

 from organic chemistry in illustration, viz. the chlorides of 

 ethylene and ethylidene: — 



9 Hs b.-p. 60°, °i H2C1 b.-p. 84°. 



CHC1 2 CH 2 01 



Not only are the corresponding oxides, acetaldehyde and 

 ethylene oxide, 



9 Hs b.-p. 2i°, ? H2 y), b.-p. i3°, 



CHO OH/ 



known, but also their respective polymers paraldehyde and 

 metaldehyde, as well as the dioxide and polyoxide of ethylene. 



f Paraldehyde . . (C 2 H 4 0) 3 , liquid, boiling-point 124°. 

 \ Metaldehyde . . (C 2 H 4 0) n , solid, nonvolatile as such. 



( Ethylene dioxide (C 2 H 4 0) 2 , solid, boiling-point 102°." 

 \ Ethylene polyoxide (C 2 H 4 0) w , solid, volatile with difficulty. 



This interpretation of oxides being admitted, it is no longer 

 a hypothesis, but a fact, that the physical state and thermal 

 properties, notably the fusibility and volatility, are a direct 

 function of the molecular weight, and every abnormal relation, 

 from the physical point of view, between the chlorides and 

 oxides ceases immediately. The infusibility and fixity of the 

 latter, so strange at first sights return into the natural order 

 of things. 



We have, therefore, to prove the following proposition: — 

 The known oxides, and notably the metallic oxides, are 

 polymers n(RO x ) of the true oxides RO^, corresponding to the 

 chlorides RCl 2: c. 



Proofs of the Polymerization of the Oxides. 



Their Additive Power.— There are no compounds which 

 are more ready to enter into combination than the oxides. 

 In fact, it would not be far from the truth to say that there is 

 no class of compounds with which they are incapable of enter- 

 ing into combination. In mineral chemistry they combine 

 by addition, and often with considerable energy, not only with 

 oxides of a contrary sign — acid oxides with basic oxides, — 

 but with all chemical compounds indiscriminately, whatever 

 may be their special function. 



