A toolbox for investigating liquid metal systems

The exceptional properties of liquid metals at room temperature, such as their fluidity, stretchability, deformability, and potential applications, have rapidly inspired the scientific community. At present, the main challenge is overcoming technical barriers associated with the characterization of liquid metal systems, which have resulted in their molecular structure remaining effectively unknown. This lack of knowledge has significantly hampered the progress of the emerging field of liquid metal chemistry, prohibiting tailored design and relegating researchers to work by trial and error. In recent years, several technological and scientific developments, including improved analytical tools, have emerged that have the potential to tackle the current challenges. In this review, we present a comprehensive appraisal of the various state-ofthe-art characterization techniques that can help uncover answers to long-standing questions in the domain of liquid metals and metal -in -metal colloidal systems. We describe selected generic methodologies and several unique approaches that can capture the various changes in the physical and chemical behavior of molten metals in the presence of internal and external stimuli. In combination, the outlined tools will deepen our understanding of liquid metal chemistry and will accelerate research translation to provide solutions in areas such as catalysis, biomedicine, and reconfigurable electronics.