Fig. 4
Monoclinic crystal structure of Fe4O5-III-a. This structure has C2/m symmetry and plots are based on the crystal structure data refined at 11.7 GPa and 180 K. a Projection of the trigonal prisms Fe1 and single chains of Fe2 octahedra. b The unit cell projected down the b-axis. Thin solid lines indicate the unit cell edges. c Projection of the double chains of Fe3 octahedra. d Projection down the c-axis of one of the two diagonal ribbons shown in e. e Two characteristic diagonal ribbons consisting of five iron chains each. f Projection of one of two diagonal ribbons shown in e. Solid ellipsoids are dimers and trimers formed in the chains of octahedrally-coordinated iron. Dotted ellipsoids highlight Fe3–Fe1 pairs with shortened Fe–Fe length. Different crystallographic positions are shown in different colors. g Bond valence sums (BVS) values of all the iron cations in the crystal structure
