Fig. 3.

Magnetic structures for the two phases of CaFe₃O₅. Fe1/Fe2 spins are shown in red/blue and Ca ions in purple. a Magnetic structure of the charge ordered (CO) phase CaFe₃O₅ with propagation vector (½ 0 0), with lines showing ferromagnetic order within trimerons. b Magnetic structure of the charge averaged (CA) phase, with (0 0 0) propagation and lines showing the ferromagnetic chain parallel to the x axis. c A trimeron unit as found in the CO structure (a) with bonding electron density represented as an ellipsoid. The size of the t_2g orbitals approximates the atomic populations. The atomic displacement arrows indicate the elongation of the four Fe–O bonds perpendicular to the Jahn–Teller contracted axis and the shortening of the cation–cation distances due to weak Fe–Fe bonding interactions