Fig. 7
Pressure-driven Fe4O5-III → Fe4O5-IV transition. a Equation of state of Fe4O5 at 120 K showing a volume drop of ~0.5% at the Fe4O5-III → Fe4O5-IV transition. b Edge-shared diagonal ribbons of prisms and octahedra (seen in Figs. 4–6) provide channels for charge hopping between the prisms and octahedra. c Correlation between ratios of Fe–Fe distances in dimers and trimers to those in gaps between them \(\left( {d_{{\mathrm{Fe}} - {\mathrm{Fe}}}^{{\mathrm{units}}}/d_{{\mathrm{Fe}} - {\mathrm{Fe}}}^{{\mathrm{gap}}}} \right)\) and absolute deviations of bond valence sums (BVS) values of iron in these chains from 2.5+. d Model demonstrating the coexistence of several charge-ordered phases in a single crystal of Fe4O5. The electron transfer from the prisms to octahedra leads to a short-range reorganization of ordering type
