IODINE CHELSEA, JACOB, DAN

CHARACTARISTICS Iodine is a bluish-black, lustrous solid. Although iodine is a non-metal, it displays some metallic properties. When dissolved in chloroform, carbon tetrachloride or carbon disulphide, Iodine yields purple colored solutions. It is barely soluble in water, giving a yellow solution.

In pure form, iodine is a lustrous substance with a purple to black color. It vaporizes into a lovely blue-purple gas which also happens to be quite toxic. Pure iodine is corrosive and poisonous, and it should be handled very carefully, ideally while wearing gloves and face protection.

SOURCE In nature, iodine occurs in the form of iodide ions, mainly in seawater. It is introduced into the food chain via seaweed and other sea- plants. Iodine is found in some minerals and soils. Commercially, iodine is obtained in several ways, such as taking iodine vapor from processed brine, by ion exchange of brine or by releasing iodine from iodate taken from nitrate ores.

USES Iodine is important in medicine, in both radioactive and non-radioactive forms. A solution containing potassium iodide (KI) and iodine in alcohol is used to disinfect external wounds. Elemental iodine is also used as a disinfectant. Silver iodide is used in photography. Iodine is sometimes added to table salt to prevent thyroid disease. Iodine's other uses include catalysts, animal feeds and printing inks and dyes.

Pure iodine is toxic. It should not be ingested or handled with bare hands, and the vapor is very irritating so it should be handled in a well ventilated area. Since iodine is so volatile, it is important to be careful about handling it with other chemicals. Iodine solutions such as those used to disinfect surgical patients are safe to handle although they should not be ingested.

HARMFUL EFFECTS In small doses, iodine is slightly toxic and it is highly poisonous in large amounts. Elemental iodine is an irritant which can cause sores on the skin. Iodine vapor causes extreme eye irritation.

TITLE Many people are familiar with iodine in the form of a solution used in the field of medicine as a germicide or antiseptic. Iodine can also be used to produce a purple dye, and its radioactive isotopes are used in medical diagnosis. Radioactive iodine can be used to treat thyroid cancer and as a tracer in the body to determine how well the thyroid is functioning.

TITLE Humans need around 140 micrograms of iodine a day; this dietary iodine is usually taken in through fish, sea vegetables, and other foods of marine origin. In many parts of the world, iodine is added to salt to ensure that people get enough dietary iodine; this product is known as iodized salt.

TITLE The element was discovered in 1811 by Bernard Courtois, who was working with seawater to extract sodium carbonate. He did not measure his chemicals correctly, and he ended up producing a purple vapor which quickly crystallized into iodine. Most iodine today is extracted from caliche, a mineral compound which contains iodine, rather than seawater.

TITLE Iodine is a naturally occuring chemical. Small amounts are needed for good health. However, large doses can cause harm. Children are especially sensitive to the effects of iodine. NOTE: Iodine is found in certain foods. However, there is normally not enough iodine in foods to harm the body.

IODINE POISIONING Note: This list may not be all inclusive. Symptoms Abdominal pain Coughing Delirium Diarrhea Fever Metallic taste in mouth Mouth and throat pain No urine output Seizures Shock Shortness of breath Stupor Thirst Vomiting

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