CONSTITUTION AND TEMPERATURE ON MAGNETIC SUSCEPTIBILITY. 
O Q 
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benzene itself, but the presence of a halogen atom destroys the symmetry of the 
complex, the latter being sheared in various directions, it is by a process of shearing, 
similar to that which corresponds to the change from the cubically to the hexagonally 
derived complex, that we may account for the different diamagnetic properties 
accompanying polymorphism and by which we may, at any rate provisionally, explain 
the abnormal results obtained with benzoyl chloride and phenylhydrazine. Diagram - 
matically, we may represent such a shear by the accompanying figures (a) and (b), 
where the black dot represents the substituent of the benzene complex. During 
crystallization it frequently happens that pairs of molecules assume mirror-image 
positions—-(a) and (b) are types of this arrangement. In the case shown at (c), the 
mirror-image formation is absent. The forces of crystallization will be different 
in the three cases. On the whole, the resultant of the forces between the molecules 
will act inwards on each ring system in case (a), and outwards in case (b). Each of 
these types differs from (c) where the forces on the whole may act neither inwards 
nor outwards on any given ring system. 
Hence we may regard the substituent as a directive agent, and in so far as it 
influences its own complex and the neighbouring complexes, there is a reversal of the 
effects produced by the forces of crystallization in case (b) as compared with case (a). 
This reversal of the interaction of substituent and nucleus with respect to any 
particular molecule will produce a distortion of the internal structure of an opposite 
kind. 
For convenience and clearness the disposition of the six carbon atoms of the 
benzene ring is represented as uniplanar. This need not be the case. It is possible 
now to explain the two abnormal cases of benzoyl chloride and phenylhydrazine 
without having to assume that the liquid state possesses a greater molecular 
complexity or a closer packing of molecules than the corresponding crystalline state. 
I have had the opportunity of discussing, with Prof. Pope, this question of a reversal 
of the change in magnetic property due to crystallization, and he informed me that 
the demands of this explanation are in accordance with the modern views of chemists 
and crystallographers. 
The nature of the irregularity of the x — ^ curves does not appear to be directly 
