INERTIA OF CARBON COMBINATION 97 



Although very strong forces favour the oxidation, graphite 

 is so protected from them that it can be used for making 

 crucibles, whilst the imflammability of diamond was only 

 discovered very late, for the same reason. 



On the other hand compounds of carbon are known, such 

 as acetylene, that break up with a large evolution of heat, 

 so that strong forces are tending to decompose them, and 

 yet possess a relatively, often strikingly great stability. 

 In the same way it is amongst the carbon compounds that 

 isomerism is observed, since that implies that less stable 

 forms are capable of continued existence l . Thus all the 

 hydrocarbons of the formula C 6 H ]4 can be prepared and 

 kept, whilst among inorganic compounds of the formula 

 P0 3 NH G , e.g. only two ammonium phosphates and hydro- 

 xylamine hypophosphite can be obtained, and of these the 

 latter slowly decomposes. 



Thus, in consequence of this inertia, it is the chemistry 

 of the carbon compounds that is the region of slow reac- 

 tions, and consequently of measurements of velocity ; 

 finally we may recall that the most important principle in 

 determining constitution (Part II, p. 87) depending on the 

 fact that in a reaction the least number of linkages possible 

 is broken is the immediate consequence of the inertia here 

 mentioned. 



It cannot be overlooked that this last peculiarity in the 

 phenomena of affinity is also to be brought into connexion 

 with the positive or negative character. If that is pro- 

 nounced, then as seen on p. 91 ionization, i. e. breaking up 

 and loosening is favoured, which leads in salts, &c., to 

 instantaneous reaction. In carbon which stands just in 

 the middle (p. 93) and is neutral, this cause favouring 

 reaction is wanting. 



SUMMARY. 



The preceding four characteristics of the elements in 

 regard to affinity may be brought under a single point of 



1 Hantzsch, Ann. der Chemie, 292. 340. 

 G 



