Iodine

Discovered by In 1811 when Bernard Courtois (1777-1838)

Discovered while trying to make a poison not a cure

Tried discovering a weapon to use against Napoleon and his army

Discovery

Jean Lugol discovered that bonding iodine to a mineral (potassium) made it water soluble

Iodine naturally dissolves in alcohol, but not in water until it is first bonded to the elements potassium or chlorine.

Discovery

Swiss physician, Dr Jean François Condet announced that iodine could reduce goiters (enlarged thyroids).

People started using it whenever they felt sick (thought of as a “cure-all”)

Discovery

Atomic Number: 53 Atomic Symbol: I Atomic Weight: 126.9045 Electron Configuration: 2-8-18-18-7 Melting Point: 113.5oC Boiling Point: 184oC

Information

Iodine is a bluish-black solid that at room temperatures into a blue-violet gas with an irritating odor

It forms compounds with many elements, but is less active than the other halogens, which displace it from iodides.

It dissolves readily in chloroform, carbon tetrachloride, or carbon disulfide to form purple solutions.

It is only slightly soluble in water

Properties

Iodine compounds are important in organic chemistry and very useful in medicine.

Thirty isotopes are recognized. Only one stable isotope, 127I is found in nature.

The artificial radioisotope 131I, with a half-life of 8 days, has been used in treating the thyroid gland.

Uses

The most common compounds are the iodides of sodium and potassium (KI) and the iodates (KIO3).

Lack of iodine is the cause of goiter. Iodides, and thyroxin which contains iodine, are used internally in medicine, and as a solution of KI and iodine in alcohol is used for external wounds.

Potassium iodide finds use in photography. The deep blue color with starch solution is characteristic of the free element

More Uses

Care should be taken in handling and using iodine, as contact with the skin can cause lesions

Iodine vapor is intensely irritating to the eyes and mucous membranes.

Handling

Chronic iodine deficiency can lead to numerous health problems in children and adults, including thyroid gland dysfunction (including goiter) and various neurologic, gastrointestinal, and skin abnormalities.

Use in Medicine

Sumatra, Indonesia.

This is a massive goiter caused by the continued lack of iodine (a micronutrient) in his diet. This is a condition both preventable and treatable with just pinches of iodized salt. But, unlike western countries, the sale of uniodized salt is not regulated in developing countries.

Picture from yahoo.com

The End