126 Dr. Carnelley on the Influence of Atomic Arrangement 





Ben- 

 zene. 



Mono- 

 deriva- 

 tive. 



Di- 



deriva- 

 tive. 



Tri- 



deriva- 

 tive. 



Tetra- 

 deriva- 

 tive. 



Penta- 



deriva- 

 tive. 



Hexa- 



deriva- 



tive. 



Position of side chains... 







1 



1.4 



1.3.5 



1.2.4.5 



1.2.3.4.5 



1.2.3.4.5.6 



The side chains being — 

 CH, 



7 



:< 



7 

 7 

 7 



Liquid 

 Liquid 

 at -40 

 b.-20 

 Liquid 



15 



l53 



J 89 



127 

 171 



Liquid 

 635 

 119 



80 

 138 

 140 



50 



74 



a 240 



164 

 226 

 a 310 



CI 



Br 



I 



NO, 



NH, 



-8 1 147 









Influence of Compactness, or number of Side Chains on the 

 Melting- and Boiling-points. 



Lothar Meyer has pointed out, in his ' Modern Theories of 

 Chemistry,' p. 280, " that, of any number of isomeric compounds, 

 those are the most volatile in which there are the greatest number 

 of side chains, or in which the main chain of atoms is most 

 branched, and therefore in which the main chain is the shortest." 



From the observation of a great number of compounds, I 

 cannot help concluding that a rule the exact reverse of the 

 above holds good as regards the melting-point, viz. that those 

 isomeric compounds melt the highest in which there are the 

 greatest number of side chains. This has already been indi- 

 cated to some extent above, where it has been pointed out that 

 the greater the compactness of the molecule the higher the 

 melting-point. The above rules may be illustrated as fol- 

 lows : — 





Boiling- 

 point. 



Meltiug- 

 point. 



I- 



a 



P4 



fCH 3 .CH 2 .CH 2 .CH 2 .CH 3 



38 

 30 



9-5 



Liquid. 

 Liquid. 



-20 





CH 3 



1 

 CH 3 — C— CH 3 



1 

 I CH 3 



I" 



6 



fCH J -CH,.CH 2 .CH,.CH 2 .CH > .CIL,CH 3 

 gH^CH-CH^-CH/CH, 



1 1 



CH 3 — C— C— CH, 



125 



108 



105 



Liquid. 

 Liquid. 



96-97 





II 3 

 ^ CH 3 CH 3 



