Packing densest molecular

The symmetry of the crystal structure is a direct consequence of dense packing. The densest packing is when each building element makes the maximum number of contacts in the structure. First, the packing of equal spheres in atomic and ionic systems will be discussed. Then molecular packing will be considered. Only characteristic features and examples will be dealt with here, following Kitaigorodskii [38]. ... 

The new polar symmetry allows for the existence of macroscopic polarization, large or small, depending on the magnitude of the strain and molecular dipole moments shown by small arrows. Due to the distortions, the densest packing of our pears and bananas results in some preferable ahgimient of molecular skeletons in such a way that molecular dipoles look more up than down. By definition, the dipole moment of the unit volume is electric polarization. These simple arguments brought R. Meyer to the brilliant idea of piezoelectric polarization [25] ... 

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