Key points are not available for this paper at this time.
The rate of intramolecular electron transfer changes from > 109 s−1 at 4.2 K to < 107 at 350 K when I is exchanged for PF in the mixed-valence solid diiodobiferrocenium salt 1. This is revealed by Mössbauer and EPR spectra. Coulomb interactions between cation and surrounding anions are decisive for the rate of electron transfer.
Webb et al. (1989) studied this question.