Used in density gradient centrifugation to separate biological molecules like DNA, RNA, viruses, and ribosomes based on buoyant density. Commonly employed in molecular biology and biochemistry research.

Serves as a source of caesium ions in specialized chemical reactions 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.

Has been explored in some medical applications, such as experimental treatments for certain cancers, but its use is controversial, not widely accepted, and requires high caution due to toxicity.