The Chem. Sci. journal features on its front cover of the November 2025 issue the research article “Mimicking sMMOH chemistry: trapping the Sc3+-bound nonheme FeIII–O–O–FeIII adduct prior to its conversion into an FeIV2(m-O)2 core” by Prof Marcel Swart in collaboration with Prof. Lawrence Que (University of Minnesota). Di-iron systems that activate O2 to form high-valent, oxo-bridged FeIV2 or FeIIIFeIV products