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Polyhedra structure of the most prominent POM archetypes. In every structure the POM-forming addenda metals (M) are shown as cyan polyhedra, heteroatoms (X) either as brown polyhedra or brown sphere and oxygen atoms as small red spheres on the edges of the addenda metal polyhedra. (A) Keggin archetype. (B) Wells–Dawson archetype. (C) Anderson–Evans archetype. (D) Lindqvist archetype. (E) Preyssler archetype viewed along the fivefold axis.
