- iodine (n.)
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- non-metallic element, 1814, formed by English chemist Sir Humphrey Davy (1778-1829) from French iode "iodine," which was coined 1812 by French chemist Joseph Louis Gay-Lussac from Greek ioeides "violet-colored" (from ion "the violet; dark blue flower;" see violet) + 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.