Figure 5

Crystal and magnetic structure in \(\hbox {Fe}_2\hbox {Se}_2\hbox {O}_7\) found from the neutron diffraction experiments. The thick solid, dashed, dotted, and thin solid lines indicate the dominant exchange at Fe(1)–Fe(2) (\(J_\mathrm {bb}\)), Fe(2)–Fe(3) (\(J_\mathrm {vb2}\)), Fe(1)–Fe(3) (\(J_\mathrm {vb1}\)), and Fe(3)–Fe(3) (\(J_\mathrm {vv}\)) bonds indicated by the DFT calculations, respectively. The rectangles indicate the unit cell. The figure is illustrated using VESTA software (Ver.3.5.7, https://jp-minerals.org/vesta/en/)²⁷.