Theory of Molecular Volumes. 461 



Alkaloids. 



Compound. M.V. SA.V. A for Eing. K. 



a Coniin, C 8 H 17 N [176-6] 192-2 -15'6 '52 



from C 6 H 5 C 3 H r 



CH,— CH-CH -CH,-CH 3 



/ \ 



CH. NH 



\ / 



€H 2 -CH 2 



Nicotene, C 10 H 14 N 2 ... [196*0] 222'0 -26-0 '50 

 CH CH 



-26-0 



I I A 



CH C — CH CH 2 



CH I 



CH 2 — CH, 



27*£ above extended study of ring compounds has shown that 

 molecular volume is undoubtedly influenced by ring structure 

 to an extent dependent on the number of groups in the ring and 

 on th* number of rings. 



The magnitudes of the contractions have been in all cases 

 verified by experimental results. The effect in general is a 

 contraction which is contributed to by all the elements of 

 the nucleus and often certain atoms associated with it. 



(a) One remarkable fact is, that it makes no difference 

 whether the rings are separated or condensed — the contraction 

 in both cases is the same. It follows that owing to the super- 

 posed effects, the common atoms of the two or three rings 

 must have extraordinarily small volumes {vide infra). 



This fact enables us to distinguish condensed ring from 

 separate ring structure in an unknown compound. Thus in 

 Naphthalene Acenaphtene 



CH CH CH CH 



• \ / \ # \ / \ 



CH C* CH CH C* 



I and 



CH C* CH CH C'** CH 



% / N ■ . • V- / ; \ "• 



CH CH C* C* 



I I 

 CH = CH 



the carbons C* and C** are subject to extra contractions, 

 owing to overlapping effects. 



