Used in medicine for the treatment of iodine deficiency and as a radiocontrast agent in diagnostic imaging. It serves as a source of stable iodine to prevent thyroid damage during radiation emergencies. In nuclear medicine, it is employed in radioactive form (I-131 or I-123) for thyroid function tests and therapy of thyroid disorders. Also used in organic synthesis as a catalyst or reagent, particularly in Finkelstein reactions. In industry, it acts as a scavenger for mercury in environmental cleanup and is utilized in scintillation detectors for radiation monitoring due to its ability to emit light when exposed to ionizing radiation.