Iodine has nutritional, medicinal and chemical uses. Iodine happens to be a constituent of various pharmaceutical products, printing inks, dyes, photographic chemicals, animal feeds and industrial catalysts. Iodine is a brilliant black shiny crystalline substance, and it dissolves in alcohol to form an antiseptic solution.
The main source of iodine is sea-water where it is present at concentrations of about 0.05 parts per million. Commercial production of iodine is done by extraction of iodine vapor from processed brine, liberation of iodate from nitrate ores or ion exchange in brine.
Iodine is an essential element in the human body. It aids in the proper functioning of the thyroid gland to produce thyroid hormones. Human beings get iodine from food. The quantities of iodine in food are, however, very small which necessitates supplementation, which is achieved by iodization of table salt.
Inadequate iodine in the human body causes the thyroid gland to work harder, which leads to an enlargement of the thyroid gland in the neck, which is a sign of goiter. Iodine deficiency can also lead to infertility in women, and a compromised immunity. Some researchers suggest that iodine deficiency raises the risk of thyroid cancer and other cancers.
Bernard Courtois discovered iodine in 1811 while trying to extract potassium from seaweed. After extracting the potassium from seaweed, he added sulfuric acid to the remaining liquid. The purple crystals resulting from this procedure helped give this element its name. The Greek word iodes means violet.
Iodine is slightly toxic and can be dangerous in large amounts. Pure iodine is a skin irritant, and the vapor is known to cause eye irritation.