Figure 1.

Schematic view (left) and structural representation (right) of [L₂Fe₂S₂]ⁿ compounds, where n = 2-, 3-, 4- corresponds to diferric, mixed-valent, and diferrous forms, respectively, and L = bis(benzimidazolato). Color code: yellow - sulfur; orange - iron; blue - nitrogen; light brown - carbon; white - hydrogen.²⁸⁻³⁰