Used in density gradient centrifugation to separate biological molecules like DNA and viruses based on buoyant density. Commonly employed in molecular biology for plasmid DNA purification. Also utilized in medical applications, such as in radiation therapy for certain cancers, due to its ability to carry radioactive isotopes. Serves as a source of caesium ions in chemical synthesis and in the preparation of other cesium compounds. Occasionally used in photoelectric cells and scintillation counters because of its electrical conductivity and response to light. Handle with care due to high toxicity.