512 PRINCIPLES OF CHEMISTRY 



crystals of the monochloride, it is easy to obtain iodine trichloride ia 

 orange crystals, which melt at 34 and volatilise at 47, but in so doing 

 decompose (into C1 2 and C1I). The chemical properties of these 

 chlorides entirely resemble those of chlorine and iodine, as would be 

 expected, because, in this instance, a combination of similar substances 

 has taken place as in the formation of solutions or alloys. Thus, for 

 instance, the unsaturated hydrocarbons (for example, C 2 H 4 ), which 

 are capable of directly combining with chlorine and iodine, also directly 

 combine with iodine monochloride 



