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1814, formed by English chemist Sir Humphrey Davy (1778-1829) from French iode "iodine," coined 1812 by French chemist Joseph Louis Gay-Lussac from Greek ioeides "violet-colored," from ion "the violet; dark blue flower," + eidos "appearance" (see -oid). Davy added the chemical suffix -ine (2) to make it analogous with chlorine and fluorine. So called from the color of the vapor given off when the crystals are heated.
iodine i·o·dine (ī'ə-dīn', -dĭn, -dēn')
Symbol I A poisonous halogen element having compounds used as germicides, antiseptics, and food supplements, with radioactive isotopes, especially I 131, used in thyroid disease diagnosis and therapy. Atomic number 53; atomic weight 126.9045; melting point 113.7°C; boiling point 184.4°C; specific gravity (solid, at 20°C) 4.93; valence 1, 3, 5, 7.
A liquid containing iodine dissolved in ethyl alcohol, used as an antiseptic for wounds.
A shiny, grayish-black element of the halogen group. It is corrosive and poisonous and occurs in very small amounts in nature except for seaweed, in which it is abundant. Iodine compounds are used in medicine, antiseptics, and dyes. Atomic number 53; atomic weight 126.9045; melting point 113.5°C; boiling point 184.35°C; specific gravity (solid, at 20°C) 4.93; valence 1, 3, 5, 7. See Periodic Table.