Sonochemistry of molten metals

Ultrasonic irradiation of molten metals in liquid media causes dispersion of the metals into suspensions of micro- and nanoparticles that can be separated. This is applicable mainly to low-m_p elemental metals or alloys, but higher m_p elemental metals or alloys were also reported. Among metals, mercury and gallium exhibit especially-low melting points and are thus considered as liquid metals (LMs). Sonication of mercury in aqueous solutions of certain metal ions can cause simultaneous reduction of the ions and reactions between the metals. Gallium can be melted and sonicated in warm water, as well as in aqueous solutions of various solutes such as metal ions and organic compounds, which opened a wide window of interactions between the gallium particles and the solutes. Sonication of molten metals in organic liquids, such as polyethylene glycol (PEG) 400, forms carbon dots (C-dots) doped with nanoparticles of these metals. This review article summarizes the various interactions and reactions that occur upon sonication of metals in liquid media.