Interplay between charge and structural ordering in mixed-valence biferrocenium salts

A model of charge and structural ordering in mixed-valence biferrocenium salts is proposed. The model involves electron transfer, the interaction of each cluster ion with full symmetric and nonsymmetric vibrations of the nearest surrounding as well as intercluster dipole-dipole interaction. Different types of charge and structural ordering are shown to be possible. The interrelation between structural distortions and electron localization is revealed. The role of local nonsymmetric vibrations in electron localization is considered.