Electron Theory in Organic Chemistry. 



671 



for the influence of 2 on 4 is negligible, as has been 

 pointed out. 



5. We will now consider the effect of unsaturation on 

 neighbouring saturated groups. As has been pointed out, 

 the stabilizing effect of unsaturation on neighbouring satu- 

 rated groups, e, g. methyl, is negligible. 



There is, however, another way in which they may influ- 

 ence the stability of neighbouring saturated groups. Taking 

 as example the — CH 3 group, the configuration of two 

 hydrogens and the carbon (omitting the third and reducing 

 the system for clearness to one plane) is as shown in fig. 2, 

 the notation being as in fig. 1. 



Fig. 2. 



*H 



P 



*H 



The stabilizing influence on « is made up of that due to a! 

 and that due to (3. 



Now an unsaturated electron, while not adding anything 

 appreciable to the stability of this part of the system for 

 reasons given above, may nevertheless alter the positions of 

 the orbits a, a', /3, and so their stabilizing effects on one 

 another, for the stabilizing factor, depending as it does on 



(Y> * s °f a l° Wf)r order of magnitude than the force 

 (due to electromagnetic effect) between the orbits, which 



A 1 8M 



depends on -^p 



To discuss the change in stability due to this is at present 

 impossible, as it requires a considerable knowledge of the 

 velocities of the electrons and directions of their orbits. The 

 above, however, does show that such a change should exist. 



Experimental evidence shows that the carbon-halogen 





