Polyoxometalates (POMs) are an established family of metal–oxygen clustered compounds. Their unique properties, discovered over the last century, have allowed them to find applications in catalysis, reaction technology, biochemistry and biomedicine. These materials are used in sustainable and green chemistry processes or in the fight against different diseases due to their solubility in water, a green and environmentally friendly solvent. In addition, the solubility is easy to tailor for t...