Fig. 2: Side view of the stepped surface.
From: Thermodynamic feasibility of the four-stage chloride-induced depassivation mechanism of iron

The oxygen vacancy is shown using a dashed circle. The simulation box is represented using the black dotted line. Fe and O atoms are shown as larger pink and smaller red spheres, respectively. The edge Fe atom is shown in orange. This color scheme is used throughout the paper unless otherwise specified. All atoms below the blue horizontal dashed line are fixed during the calculation.