Iodine

History

Iodine (Gr. iodes meaning violet) was discovered by Barnard Courtois in 1811. He was the son of a manufacturer of saltpeter (potassium nitrate, a vital part of gunpowder). At the time France was at war and gunpowder was in great demand. Saltpeter was isolated from seaweed washed up on the coasts of Normandy and Brittany. To isolate the potassium nitrate, seaweed was burned and the ash then washed with water. The remaining waste was destroyed by adding sulfuric acid. One day Courtois added too much sulfuric acid and cloud of purple vapor rose. Courtois noted that the vapor crystallized on cold surfaces making dark crystals. Courtois suspected that this was a new element but lacked the money to pursue his observations.

Related Topics:
Gr. - Barnard Courtois - 1811 - Saltpeter - France - Normandy - Brittany - Sulfuric acid

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However he gave samples to his friends, Charles Bernard Desormes (1777-1862) and Nicolas Clément (1779-1841) to continue research. He also gave some of the substance to Joseph Louis Gay-Lussac (1778–1850), a well-known chemist at that time, and to André-Marie Ampère (1775-1836). On November 29 1813 Dersormes and Clément made public Courtois’ discovery. They described the substance to a meeting of the Imperial Institute of France. On December 6 Gay-Lussac announced that the new substance was either an element or a compound of oxygen. Ampère had given some of his sample to Humphry Davy (1778-1829). Davy did some experiments on the substance and noted its similarity to chlorine. Davy sent a letter dated December 10 to the Royal Society of London stating that he had identified a new element. A large argument erupted between Davy and Gay-Lussac over who identified iodine first but both scientists acknowledged Bernard Courtois as the first to isolate the element.

Related Topics:
Charles Bernard Desormes - 1777 - 1862 - Nicolas Clément - 1779 - 1841 - Joseph Louis Gay-Lussac - 1778 - 1850 - André-Marie Ampère - 1775 - 1836 - November 29 - 1813 - December 6 - Humphry Davy - 1829 - December 10 - Royal Society of London - Element

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