Isolation of Blackberry-Shaped Nanoparticles of a Giant {Mo₇₂Fe₃₀} Cluster and Their Transformation to a Crystalline Nanoferric Molybdate

When an aqueous solution of sodium molybdate is added to an aqueous solution of ferric chloride, acidified with acetic acid, a giant {Mo₇₂Fe₃₀} cluster is instantaneously formed as the amorphous substance Na₂­[Mo₇₂Fe₃₀O₂₅₂­(CH₃COO)₄­(OH)₁₆­(H₂O)₁₀₈]·180 H₂O (<b>1</b>). Compound <b>1</b> consists of aggregated nanovesicles of {Mo₇₂Fe₃₀} clusters, as confirmed by field-emission scanning electron microscopy and transmission electron microscopy images of <b>1</b>. An aqueous suspension of <b>1</b> upon moderate heating results in the formation of crystalline nanoferric molybdate, which gives insight into understanding the formation of a yellow coating mineral, ferrimolybdite, frequently found on the ores of molybdenum