This gland helps to regulate growth and body temperature. Normally we get enough iodine from the food we eat. A deficiency of iodine can cause the thyroid gland to swell up known as goitre. Natural abundance. Iodine is found in seawater, as iodide. It is only present in trace amounts 0. In the past iodine was obtained from seaweed. Now the main sources of iodine are iodate minerals, natural brine deposits left by the evaporation of ancient seas and brackish briny waters from oil and salt wells.
Iodine is obtained commercially by releasing iodine from the iodate obtained from nitrate ores or extracting iodine vapour from the processed brine. Help text not available for this section currently. Elements and Periodic Table History. In the early s, Bernard Courtois of Paris manufactured saltpetre potassium nitrate, KNO 3 and used seaweed ash as his source of potassium.
One day in , he added sulfuric acid and saw purple fumes which condensed to form crystals with a metallic lustre. Courtois guessed this was a new element. In November , they exhibited iodine at the Imperial Institute in Paris. Davy sent a report to the Royal Institution in London where it was mistakenly assumed he was the discoverer, a belief that persisted for more than 50 years. Atomic data. Bond enthalpies. Glossary Common oxidation states The oxidation state of an atom is a measure of the degree of oxidation of an atom.
Oxidation states and isotopes. Glossary Data for this section been provided by the British Geological Survey. Relative supply risk An integrated supply risk index from 1 very low risk to 10 very high risk. Recycling rate The percentage of a commodity which is recycled. Substitutability The availability of suitable substitutes for a given commodity. Reserve distribution The percentage of the world reserves located in the country with the largest reserves. Political stability of top producer A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators.
Political stability of top reserve holder A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.
Supply risk. Relative supply risk 6. Young's modulus A measure of the stiffness of a substance. Shear modulus A measure of how difficult it is to deform a material. Bulk modulus A measure of how difficult it is to compress a substance. Vapour pressure A measure of the propensity of a substance to evaporate. Pressure and temperature data — advanced.
Listen to Iodine Podcast Transcript :. You're listening to Chemistry in its element brought to you by Chemistry World , the magazine of the Royal Society of Chemistry.
Hello, this week cretins, fire crackers and clean water. The story starts in Italy, and here's Andrea Sella. When I was a child, I used spend a couple of weeks each summer high in the Italian Alps in an idyllic little village called Cogne that nestles quietly between high ice-clad peaks. To most Italians the name is associated with a sensational murder. Others know that in winter the valley has some of the finest ice-climbing in the Alps.
But to me, Cogne will always be connected with the element iodine. One afternoon, when I was around 10 years old, returning with my Dad from a long hike, we passed a dull grey building on the edge of the village. It was surrounded by a tall metal fence and had an institutional look about it. Sitting on the bench all on his own was a strange looking old man - he had rather shaggy hair, a vacant look, and a large, distended pouch of skin where his neck should have been.
I was utterly shocked by this strange being. I pestered my father with questions. Who was he? What was wrong with him? Why did he look so sad? My father, whose patience in the face of a barrage of questions was almost infinite, explained that the poor man had grown up with insufficient iodine in his diet.
Iodine, he went on was essential for the proper development of the thyroid gland in the neck, and that if one didn't eat the right kind of salt, especially as a child, one might develop goitre and one's mental development would also be affected. I would later read of English travellers passing through the Alps referring to The Valleys of the Cretins - travel books of the period often include lurid illustrations of these poor unfortunates.
The disease had been known to medical writers for centuries. Galen for example recommended treatment with marine sponges. In Roger of Salerno recommended seaweed. Similar suggestions were also made in China. Paracelsus, the great renaissance healer, alchemist, and writer was one of the first to spot the connexion between goiter and cretinism, and first suggested that minerals in drinking water might play a role in causing the condition.
But what these mysterious minerals might be was a mystery. In a young French chemist, Bernard Courtois, working in Paris stumbled across a new element. His family's firm produced the saltpetre needed to make gunpowder for Napoleon's wars. To do this they used wood ash. Wartime shortages of wood forced them instead to burn seaweed, which was plentiful on the coastlines of northern France. Adding concentrated sulphuric acid to the ash, Courtois, obtained an astonishing purple vapour that crystallized onto the sides of the container.
It has been suggested that Iodide as an antioxidant be merged into this article. Discuss Proposed since April Categories : Articles to be merged from April Articles with invalid date parameter in template All articles to be merged Anions Iodides Leaving group. Cookies help us deliver our services. By using our services, you agree to our use of cookies.
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