Iodine is a chemical element with symbol I and atomic number 53. The name is from Greek ἰοειδής ioeidēs, meaning violet or purple, due to the color of elemental iodine vapor.

Iodine and its compounds are primarily used in nutrition, and industrially in the production of acetic acid and certain polymers. Iodine's relatively high atomic number, low toxicity, and ease of attachment to organic compounds have made it a part of many X-ray contrast materials in modern medicine. Iodine has only one stable isotope. A number of iodine radioisotopes are also used in medical applications.

Iodine is found on Earth mainly as the highly water-soluble iodide ion, I-, which concentrates it in oceans and brine pools. Like the other halogens, free iodine occurs mainly as a diatomic molecule I2, and then only momentarily after being oxidized from iodide by an oxidant like free oxygen. In the universe and on Earth, iodine's high atomic number makes it a relatively rare element. However, its presence in ocean water has given it a role in biology. It is the heaviest essential element utilized widely by life in biological functions (only tungsten, employed in enzymes by a few species of bacteria, is heavier). Iodine's rarity in many soils, due to initial low abundance as a crust-element, and also leaching of soluble iodide by rainwater, has led to many deficiency problems in land animals and inland human populations. Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities.

Iodine is required by higher animals, which use it to synthesize thyroid hormones, which contain the element. Because of this function, radioisotopes of iodine are concentrated in the thyroid gland along with nonradioactive iodine. If inhaled, the radioisotope iodine-131, which has a high fission product yield, concentrates in the thyroid, but is easily remedied with potassium iodide treatment.

Read more about Iodine:  Characteristics, Occurrence, Structure and Bonding, Production, Isotopes and Their Applications, History, Iodine Chemistry, Biological Role, Precautions and Toxicity of Elemental Iodine

Other articles related to "iodine":

Minami Kantō Gas Field - Natural Resources - Brine
... The drill well yield additional to the natural gas a brine rich in iodine ... The iodine is extracted in large scale and makes this area the second largest producer after Chile, where the iodine is extracted from the caliche ...
Cadexomer Iodine
... Cadexomer iodine is an iodophor that is produced by the reaction of dextrin with epichlorhydrin coupled with ion-exchange groups and iodine ... It is a water-soluble modified starch polymer containing 0.9% iodine, calculated on a weight-weight basis, within a helical matrix ...
Sodium-iodide Symporter - Iodine Uptake
... Iodine uptake mediated by thyroid follicular cells from the blood plasma is the first step for the synthesis of thyroid hormones ... This ingested iodine is bound to serum proteins, especially to albumins ... The rest of the iodine which remains unlinked and free in bloodstream, is removed from the body through urine (the kidney is essential in the removal of iodine from ...
Starch Indicator
... Starch forms a very dark blue-black complex with triiodide which can be made by mixing iodine with iodide (often from potassium iodide) ... However, the complex is not formed if only iodine or only iodide (I-) is present ... deep, that it can be detected visually when the concentration of the iodine is as low as 0.00002 M at 20 °C ...
Precautions and Toxicity of Elemental Iodine - Iodine Sensitivity
... Some people develop a sensitivity to iodine ... Application of tincture of iodine can cause a rash ... Some cases of reaction to Povidone-iodine (Betadine) resulted in chemical burns ...

Famous quotes containing the word iodine:

    During Prohibition days, when South Carolina was actively advertising the iodine content of its vegetables, the Hell Hole brand of ‘liquid corn’ was notorious with its waggish slogan: ‘Not a Goiter in a Gallon.’
    —Administration in the State of Sout, U.S. public relief program (1935-1943)