Mobility and Form of Molecules in Relation to Lattice Structure

Internal Mobility and Form of Molecules in Relation to Lattice Structure 

The phenomena of polymorphism show immediately that individual atoms in organic molecules assume different arrangements under changing external conditions. Thus, for example, in tetrabromomethane the individual molecule possesses tetrahedral symmetry above 45°C., whereas below this temperature it possesses less symmetry in the monoclinic form. A change has, therefore, occurred in the positions of the bromine atoms 

Handhuch der Physik. Second edition Berlin 1936, Vol. 24, part 2. 

The behavior of acids in the surface film of an aqueous solution confirms this view experimentally. According to Langmuir and Adam it must be 

For example, the space requirement of nonylic acid amounts to 25 X 10 cm2 P0J. molecule, that of sebacic acid 57 X 10 . Similar relations are to be expected in amido acids, polyhydroxyl compounds etc. 

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