88 



Prof. Louis Henry on the Polymerization 



surprising when compared with the chlorides of the same 

 elements. 



The difference between the volatility of oxygen and chlorine 

 is enormous. The former, until recently, was considered as a 

 permanent gas ; the other, on the contrary, is easily condensed, 

 and only becomes gaseous at — -33 0, 6 (Regnault). An atom 

 of oxygen weighs 16, and that of chlorine 35*5. The mole- 

 cular weights of the chlorides are consequently much greater 

 than those of the corresponding oxides. Now, of mechanical 

 or physical properties, there is not one which is more directly 

 dependent on the molecular weight than fusibility and vola- 

 tility. 



Bearing these facts in mind, we are justified in formulating 

 a priori the following propositions : — (1) Oxygen and chlorine 

 are both of them elements which are endowed with great vola- 

 tility as compared with other elements. The oxides and the 

 chlorides ought, therefore, to be volatile compounds. (2) 

 Volatility exists to a greater degree in oxygen than in chlorine. 

 The oxides ought, therefore, to be more volatile than the cor- 

 responding chlorides. The oxides ought frequently to be very 

 volatile, or even gaseous, at the ordinary temperature. 



These theoretical deductions are, in fact, realized in a good 

 number of oxygenated and chlorinated compounds, particularly 

 in the case of elements or radicals which are negative or 

 metalloidal, e. g. As, Os, Eu, &c. 





Mole- 

 cular 

 weight. 



Physical state. 



Volatility. 



rOO 



32 



87 



64 

 119 



80 

 135 



44 



99 

 154 

 237 

 182 

 263 

 168 

 198 

 208*5 

 153-5 

 395 

 342 



f Perfect gas ; formerly 



\ considered permanent. 



Gas, easily condensed. 



Gas. 



Liquid. 



Solid. 



Liquid. 



Gas. 



Liquid. 



Liquid. 



Solid. 



Liquid. 



Solid. 



Solid. 



Solid. 



Solid. 



Liquid. 



Solid. 



Solid. 



Boils -10°, 



Boils 82°. 



Boils 46°. 



Boils 82°. 



Boils -78°. 



Boils +8°. 



Boils +76°. 



Boils 182°. 



Boils 118°. 



Volatilizes about 100°. 



Volatilizes 100°. 



Volatilizes 200°. 



Boils 148° t. 



Boils 110°. 



Boils 346°. 



Boils 227°. 



loci 2 



rso 



\SOCl 2 



rso 



1S0 2 0L 



cot..! 



\ COOL 



CC1 4 



J o 2 oi 6 



\C 2 C1 4 0*... 



Os0 4 



Ru0 4 



As 2 3 



fPCL 



[PC130 



JWC1. 



1WC1 4 ... 



* CCL . COOl. 



Decomposing into PCL) + Cl 2 



