42 



SECTIONAL ADDRESSES 



seems to be quite stable at the ordinary temperature, but disappears on 

 the addition of excess of mineral acid. 



In the present state of knowledge there would appear to be only two 

 possible formulae for the aci-iorm of a nitroparaffin which would account 

 for the non-planar configuration of the anion thus established. These are : 



R 



R 



-N- 



-OH and 



O 



R 



R 



OH 



>C< N^ 



O 



As Kuhn points out, there are very grave objections to the former of 

 these, the cyclic formula. The nitro-bodies themselves are non-reactive ; 

 their aci-iorms are highly reactive. As regards their general chemical 

 behaviour, the relation between the two forms corresponds very closely 

 with that between keto- and enol-desmotropes. The saturated cyclic 

 formula for the aci-iorm is in entire disaccordance with the high chemical 

 reactivity of the compound. The alternative formula with the tri- 

 co-valent carbon atom seems, on the other hand, to be in harmony with 

 the chemical behaviour of the acz- modification, as well as in agreement 

 with its experimentally established non-planar configuration. It would 

 seem therefore that, for the present at any rate, we are bound to accept 

 the second formula in spite of the highly unusual feature which it presents 

 of the tri-co-valent carbon atom. 



The configuration of the anion is clearly indicated by the tri- 

 dimensional octet formula (Fig. 4). The distribution of the ionic charge 



Ri 



A 



R, 



+ e 

 II 



O 



o 



/ 



Fig. 4. 



is a question of considerable interest. If we were to assume equal sharing 

 of the electrons in each of the valency links by which the nitrogen atom 

 is bound to the three atoms attached to it, our formula would indicate 

 the presence of charges of — e on the carbon and the singly linked oxygen 

 atom and one of + e on the nitrogen atom, — e being the electronic 

 charge. We know, however, that there will not be equal sharing, and 

 the inequality will result in diminishing the negative charges on the carbon 

 and the singly linked oxygen. Part of the negative electricity thus re- 



