Potassium Iodide (CAS#7681-11-0)
Potassium iodide appears as white crystals, granules, or powder with a strong, bitter, saline taste. When exposed to bright light, it may gradually turn yellow due to photochemical decomposition that releases small amounts of free iodine. It is readily soluble in water, alcohol, acetone, and glycerol, and slightly soluble in ether and ammonia.
It can be prepared by reacting iodine with hot potassium hydroxide solution, followed by separation from the iodate by-product through fractional crystallization. In aqueous solution, potassium iodide can dissolve iodine to form the brown triiodide ion (I₃⁻).
The compound is widely used as an analytical reagent and in photography. It is also added to table salt to help prevent goiter and other disorders associated with iodine deficiency.
Chemically, potassium iodide is a metal iodide salt containing a potassium (K⁺) counterion. It acts as a hydroxyl radical scavenger and functions as an expectorant. As a non-radioactive source of iodine, it can help prevent the absorption of radioactive iodine (I-131) by the thyroid.
