Manchester Memoirs, Vol. Ixiv. (1920), A'o. 4 13 



On this view the oxidation of indoxyl with formation of indigo 

 white resembles the oxidation of /3-naphthol to dinaphthol, and 

 the extremely ready reduction of indigotin is well explained 

 by the peroxidic character of the substance. At the same 

 time the nitrogen atoms are not capable of forming stable 

 additive compounds and the possibility of cis-trans isomerism 

 is not indicated. The aromatic cyclic conjugation embraces 

 the whole molecule, the weakest link in the chain being the 

 partial bond connecting the oxygen atoms. 



Of other partial valency formula? the following may be put 

 forward without further comment beyond the statement that 

 the majority represent efforts to indicate the absence of basic 

 properties in nitrogen compounds and that the formula for 

 triphenylmethyl represents the third valency of the central 

 carbon atom as taken up equally by the three nuclei each of 

 which becomes partially quinonoid. Similar formulae are 

 possible for the rosaniline salts. 



* — x-^C ■' for ac i d amides and similar expressions for 



-jyt/* the carboxyl group and derivatives. 



^"T-^' — C s% ) Q " d %'- m} for isonitriles and nitriles 



respectively. 



+ /~*\ for carbon 



~ s #=£'"' % ; , /"" N iviVj; «r>d R -Th^N~R monoxide, 

 -<*-*..-'+ *„_.»' \_--\_-V---' /' ?+--'' mtrogen& 



the azo- 

 compounds 



*The decomposition, on heating, of ethyl oxalacetate into carbon monoxide 

 and ethyl malonate provides an analogy to the separation of nitrogen from so 

 many azo-derivatives. 



