Iodine

　　Main Uses

　　Medical Field:

　　It is an important raw material for preparing disinfectants and antiseptics, such as iodine tincture (tincture of iodine) and povidone-iodine. It utilizes its oxidizing properties to kill bacteria, fungi, and viruses, and is used for skin and mucous membrane disinfection as well as wound treatment.

　　It is used as a raw material for synthesizing thyroid hormones (such as thyroxine T4 and triiodothyronine T3), and clinically it can be used to treat hypothyroidism.

　　Industrial Field:

　　It serves as a catalyst or oxidizing agent in organic synthesis, participating in various chemical reactions (such as iodination reactions and oxidation reactions). It is used in the manufacture of dyes, photosensitive materials (e.g., iodine vapor in iodine tungsten lamps can extend filament life), and battery electrolytes. In the metallurgical industry, it is used for the purification of certain rare metals.

　　Research and Analysis:

　　As a chemical reagent, it is used for qualitative and quantitative analysis (such as determining substance content via iodometry, utilizing the reaction between I₂ and reducing substances).

　　In biological experiments, it is used for staining (e.g., starch turns blue upon encountering iodine, allowing for the observation of starch granules within cells).

　　Food and Agriculture:

　　Potassium iodate (rather than elemental iodine, due to iodine's ease of sublimation and strong irritancy) is added to table salt as an iodine supplement to prevent goiter.

　　In agriculture, it is used to prepare fungicides to control crop diseases.